Association between hemodialysis and patient characteristics, microbiological etiology, cardiac surgery, and mortality in patients with infective endocarditis: a nationwide study

Background

Hemodialysis and infective endocarditis are both associated with poor patient outcome. However, despite high mortality rates for each disease entity, little attention is given to patients on hemodialysis who develop infective endocarditis.

Purpose

To examine patient characteristics, microbiological etiology, cardiac surgery, and outcome among patients on hemodialysis with infective endocarditis compared with patients with infective endocarditis without hemodialysis treatment.

Methods

With Danish nationwide registries, we identified patients with infective endocarditis between 2010–2018 and linked them to microbiological data from a nationwide microbiological registry with complete blood culture data. We included patients in the hemodialysis group if they received hemodialysis treatment within 6 months prior to their first-time infective endocarditis admission. Patients not meeting this criteria were put in the non-hemodialysis group. We used Kaplan-Meier estimates for difference in mortality and Cox regression for adjusted analysis.

Results

We included 4,106 patients with infective endocarditis of which 265 (6.5%) patients were also in hemodialysis treatment (66.8% men). Patients on hemodialysis were younger (median age 66 years [IQR=54.2–74.9] vs. 72.3 years [IQR=62.3–80.4]) and had a higher burden of comorbidities including hypertension (68.7 vs. 56.9%), diabetes (47.2% vs. 18.8%), and ischemic heart disease (41.1% vs. 32.2%) compared to patients without hemodialysis treatment, all p-values <0.01. Cardiac surgery was less frequently performed in patients in the hemodialysis group than in the non-hemodialysis group (11.9% vs. 19.4%, respectively, p<0.001) and Staphylococcus aureus was more frequently the microbiological etiology of infective endocarditis in the hemodialysis group than in the non-hemodialysis group (57.0% vs. 25.3%, respectively, p<0.0001). No statistically significant difference for in-hospital mortality was found. Figure 1 shows difference in mortality between the two groups. 1- and 5-year mortality were significantly higher in the hemodialysis group than in the non-hemodialysis group (34.3% vs. 17.2% and 50.5% vs. 33.9%, respectively, p<0.00001) and in adjusted analysis hemodialysis was associated with higher 1- and 5-year mortality (hazard ratio of 2.41, 95% CI 1.85–3.13 and 2.50, 95% CI 2.05–3.05, respectively), as compared with patients in the non-hemodialysis group.

Conclusion

Patients on hemodialysis with infective endocarditis are younger, sicker and have Staphylococcus aureus as causing agent more than twice as often as patients with infective endocarditis without hemodialysis treatment. This patient group have a higher mortality and by 5 years, 75% of patients in our hemodialysis group were dead.

Funding Acknowledgement

Type of funding sources: None.

High JAK2V617F allele burden is associated with an increased burden of coronary artery calcification in MPNs

Background

Patients with the haematological cancers Philadelphia-negative Myeloproliferative Neoplasms (MPNs), have an increased risk of coronary artery and aortic valve calcification, and an increased risk of myocardial infarctions. The most common acquired mutation in MPNs, the JAK2V617F mutation, has been linked to increased risk of thrombosis.

Aims

To exam the association between the JAK2V617F mutation, its allele burden, and coronary artery and aortic valve calcification.

Methods

One hundred and sixty one patients with MPN disease from one specialized haematological outpatient clinic where included. Information on demographics, smoking, alcohol habits and co-morbidities were registered. Blood samples were drawn for determination of the JAK2V617 mutation and allele burden. Patients were examined by cardiac computer tomography in order to determine their coronary artery calcium score (CACS) and aortic valve calcification (AVC) score. The association between the JAK2V617F mutation, its allele burden and coronary artery and aortic calcification was investigated with univariate and multivariate logistic regression analysis, adjusting for age, sex, ischemic heart disease (IHD), stroke, smoking, obesity, hypertension, hypercholesterolemia, diabetes mellitus, and family history of IHD or stroke in the multivariate analysis.

Results

Of the 161 patients (52% male, mean age 65.5±10.5 years), 137 (85%) were JAK2V617F positives, and the JAK2V617F allele burden was quantified in 120. The median JAK2V617F allele burden was 12% (IQR range 6–33%). There were 42 (26%) patients with a CACS >400, and 93 (58%) patients AVC. Among the JAK2V617F positive patients, 38 (24%) had a CACS >400 and 81 (59%) had AVC. In the 32 patients with a JAK2V617F allele burden>33%, 19 (59%) had a CACS >400 and 26 (81%) had AVC. In the univariate logistic regression analysis the presence of JAK2V617F mutation was not associated with a CACS >400 (Odds Ratio (OR) 1.92, 95% confidence interval (CI) 0.62–5.98, p=0.26). Similar result was found for the analysis on AVC (OR 1.45, 95% CI 0.61–3.45, p=0.41). In contrast, a JAK2V617F allele burden >33% was significantly associated with a CACS >400 (OR 5.31, 95% CI 2.23–12.66, p=0.0002), and similarly with AVC (OR 4.14, 95% CI 1.55–11.05, p=0.0045). In the multivariate adjusted analysis, a JAK2V617F allele burden >33% was significantly associated with a CACS >400 (OR 2.08, 95% CI 0.43–10.10, p=0.36), but not with AVC (OR 0.90, 95% CI 0.27–3.03, p=0.86). In the adjusted analysis the association between a JAK2V617F allele burden >33% and CACS >400 was significant (OR3.86, 95% CI 1.14–13.09, p=0.031), but the analysis on AVC was not (OR 1.59, 95% CI 0.42–6.04, p=0.50).

Conclusion

There is a significant association between a JAK2V617F allele burden >33% and the burden of coronary calcification in MPNs, measured as a CACS >400. The association remains significant after adjustment for cardiovascular risk factors.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Region Sjællands Sundhedsvidenskabelige ForskningsfondTømrermester Jørgen Holm og hustru Elisa F. Hansens Mindelegat

The impact of statins and RAS inhibitors on the association between delayed antidiabetic treatment and the risk of cardiovascular event in patients with a first HbA1c between 48–57 mmol/mol

Background

In addition to lifestyle intervention, guidelines recommend initiation of antidiabetic (AD) treatment within 3 months of diagnosing type 2 diabetes (T2D). Yet, patients with an initial HbA1c level between 48 and 57 mmol/mol may await effects of lifestyle intervention up to 6 months. Omitting initial AD treatment and any lifestyle-induced remission, may affect initiation of statins and renin-angiotensin system inhibitors (RASi) and, thus, cardiovascular risk.

Purpose

To examine whether omission of initial AD treatment is associated with an increased 5-year risk of first-time major cardiovascular event (MACE: myocardial infarction/stroke/all-cause death) compared with well-controlled patients on AD. Further, whether lower initial use of statins and RASi could explain this excess risk of MACE.

Methods

We used Danish registers to identify patients with a first-measured HbA1c of 48–57 mmol/mol between 2014 and 2020. We included patients aged 40–80 years without prior atherosclerotic disease that were alive the following 180 days (the index date). At date of index, we divided patients into four groups according to AD treatment and achieved HbA1c (mmol/mol): well-controlled (HbA1c ≤47) on AD; poorly controlled (HbA1c ≥48) on AD; remission (HbA1c ≤47) not on AD; poorly controlled (HbA1c ≥48) not on AD. Based on a Cox-regression model and imputations of treatment values of statins and RASi from two logistic regression models, we examined to what extent the observed standardised 5-year risk of MACE within each group could be reduced if each group had the same probability of treatment initiation with statin and RASi as well-controlled patients on AD.

Results

We included 14,206 patients (median age 59 [IQR 51–68] years; 52.0% men) with the following distribution according to AD group: well-controlled on AD: 22.3%; poorly controlled on AD: 14.7%; remission not on AD: 38.3%; poorly controlled not on AD: 24.6%. Patients not on AD had lower probabilities of initiation of statins and RASi compared with patients on AD (Figure 1). Compared with well-controlled on AD, the absolute 5-year risk of MACE was increased with 3.7% (95% CI 1.6–6.1) in poorly controlled on AD; 2.1% (95% CI 0.3–3.8) in remission not on AD; 3.4% (95% CI 1.6–5.3) in poorly controlled not on AD (Figure 1 and 2). If initiation of statins and RASi were the same as in the well-controlled group on AD, patients not on AD could reduce their risk of MACE with 1.0% (95% CI 0.2–1.8) in the remission group and with 2.2% (95% CI 1.2–3.2) in the poorly controlled group (Figure 2).

Conclusions

Patients not on initial AD treatment had an increased 5-year risk of MACE, even among those who experienced remission of T2D. Lower initial use of statin and RASi seem to explain some of the excess risk of MACE in patients not on initial AD treatment. This study emphasizes the need for greater focus on primary prevention with statins and RASi in T2D, especially among patients not on AD treatment.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Research Grant from Steno Diabetes Center Sjaelland

Staphylococcus aureus bacteremia in Danish patients with cardiac implantable electronic devices: an explorative epidemiological study

Background

Device-related infection is the most common serious complication in patients with cardiac implantable electronic devices (CIED). Staphylococcus aureus accounts for up to 30% of CIED-related infections. There is a lack of scientific literature investigating risk of Staphylococcus aureus bacteremia (SAB) in CIED-patients.

Purpose

We aimed to describe the risk of SAB in Danish patients with a CIED through the years 2000–2018 compared to the background population.

Methods

Patients who received a CIED from 2000–2018 were identified from The Danish National Pacemaker and ICD Register. Patients were matched 1:5 on age and gender with the background population. We identified the primary endpoint of first time SAB from The National Danish Staphylococcus Aureus Bacteremia Database. The cumulative incidence of SAB was calculated using the Aalen-Johansen estimator, adding competing risk of death into account. Hazard ratios were estimated by Cox regression models adjusting for age and gender. Crude rates of relapse SAB, defined as a new SAB episode 14–180 days after first SAB, and device extractions were reported for all patients who survived 14 days from SAB diagnosis.

Results

We identified 79,324 CIED-patients (pacemaker (PM) = 61,227; Implantable Cardioverter Defibrillator (ICD) = 11,635; Cardiac resynchronization therapy, PM or ICD (CRT) = 6,364 and 396,590 matched controls (median age 75.5±13.3 years; 61% males). Age and gender distribution differed significantly by device type (age: PM 76.1±12.1; ICD 62.4±13.4; CRT 68.0±11.1; males: PM: 55.6%, ICD% 75.5: CRT: 80.9%). Across a mean follow-up of 5.9 (±4.6) years, we observed first episode of SAB in 1,430 (1.8%) CIED-patients, compared to 2,599 (0.7%) patients in the control population (p<0.001).

The 10-year cumulative incidence of SAB was 1.0% for controls and 2.2% for CIED patients. The risk of SAB differed substantially by device type (Figure 1). Compared to controls and adjusted for age and gender, increasing hazard ratios for SAB were observed with more advanced devices: PM 1.12 (1.11–1.13); ICD 1.36 (1.33–1.39); CRT 1.55 (1.51–1.59). However, CIED-patients with SAB did not have higher 30-day mortality rates than the non-CIED control population with SAB (Controls 34.8%; PM 35.1%; ICD 28.1% CRT 26.1%, p=0.016). Out of all SAB patients who survived 14 days from SAB diagnosis (Controls=1,672; CIED=1,107), relapse SAB occurred in 52 (3.1%) controls and in 51 (4.6%) CIED-patients (PM 4.0%; ICD 5.8%; CRT 6.3%). Device extraction within 14 and 30 days from SAB diagnosis was undertaken in less than 30% of the CIED-patients (PM: 11.3/13.6%; ICD: 22.7/27.5%; CRT: 17.4/20.1%).

Conclusion

The occurrence of SAB was higher in CIED patients compared with controls and increased with more advanced devices. There was no difference in 30-day mortality after SAB between CIED patients and controls. Relapse SAB occurred in less than 7%, despite a low percentage of early device extractions.

Funding Acknowledgement

Type of funding sources: None.

Long-term impact of persistent vegetations at 6 month followup after treatment of infective endocarditis: a substudy of the Partial Oral vs Intravenous Antibiotic Treatment of Endocarditis (POET) tria

Background

Our knowledge of changes in vegetation size throughout the course of infective endocarditis (IE) and the impact of persistent vegetations on mortality or embolization after completed antibiotic treatment is sparse. No study has previously investigated the prevalence or clinical impact of persistent vegetations on transthoracic echocardiography (TTE) at 6-months follow-up after ended IE treatment.

Purpose

To investigate the association between persistent vegetations at the 6-months TTE after treatment for IE and long-term prognosis as assessed in the POET trial.

Methods

The POET trial was a nationwide, multicenter RCT, randomizing 400 patients to either partial oral or intravenous (IV) antibiotic treatment of left-sided IE, after initial stabilization of infection using conventional IV therapy.

A persistent vegetation was defined as a vegetation seen on 6-months follow-up TTE (4–7 months) after ended antibiotic treatment for IE. In the POET trial, primary outcome was defined as 1) all-cause mortality, 2) unplanned cardiac surgery, 3) embolic events or 4) relapse of bacteremia, in the 5-year follow-up period. Patients without TTE due to death or lack of available TTE were excluded.

Results

Out of 400 patients, 20 were excluded due to death during 6-months follow-up, and 201 were excluded due to unavailable TTE, leaving 179 TTEs for analysis.

At 6-months follow-up, a persistent vegetation was seen in 30 patients (16.7%, 21 males (70%), mean age 69.6 years (SD 7.7)) (Table 1). Seventeen patients (56.7%) had a persistent vegetation on the aortic valve and 13 patients (43.3%) on the mitral valve. More patients without a persistent vegetation had undergone initial surgical treatment of IE than those with a vegetation (57.7 vs 23.3%, p=0.001). In all surgically treated patients with persistent vegetation at 6-months follow-up, the vegetation was found on another valve than the operated valve.

The composite primary outcome from 6-months follow-up and until 5-year follow-up occurred in 8 patients (26.7%) with a persistent vegetation, compared to 38 patients (25.5%) (p=1.00) without. (Table 2) In patients randomized for peroral treatment, no significant difference in prevalence of persistent vegetation was found (15 patients (50%) with persistent vegetations vs. 74 patients (49.7%) without, p=1.00).

Conclusion

The occurrence of persistent vegetations at 6 months follow-up was 16.7%. There was no association between persistent vegetations at 6-months follow-up and the occurrence of the primary outcome after 5 years follow-up, suggesting that the risk associated with residual vegetations after end of antibiotic treatment is negligible after 6-months.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Danish Heart Foundation

Temporal trends in the incidence of endocarditis among patients with a prosthetic heart valve: a nationwide study

Background

The incidence of infective endocarditis (IE) is increasing in the adult population, as is the insertion of prosthetic heart valves. Patients with prosthetic heart valves are considered at high risk of IE – a complication with a high mortality. However, data on temporal changes in the incidence of IE among patients with prosthetic heart valves from unselected cohorts are sparse

Purpose

We aimed to examine nationwide temporal trends in the incidence of IE in patients with an implanted prosthetic heart valve in Denmark from 1999 to 2018.

Methods

Using Danish nationwide health-care registries we identified all patients, who underwent heart valve implantation between 1996–2018. Crude annual incidence rates per 1,000 person years (PY) of IE were computed and presented in two year intervals. Analyses were stratified by sex and age groups (<50, 50–59, 60–69, 70–79, >80 years).

Results

We identified 26,604 patients with first time prosthetic valve implantation with a median age of 72.7 years at the time of implantation, 63.1% were men with a median follow-up of 6.5 years. We found 1,442 cases of first time IE. The IE incidence rate ranged from 5.4 /1,000 PY (95% CI 3.9–7.4) in calendar period 2001–2002 to 10.0/1,000 PY (95% 8.84–11.11) in calendar period 2017–2018 with an unadjusted increasing trend during the study period (ptrend<0.0001), (Figure 1). Overall, men had a higher crude incidence rate compared with women, however no significant temporal changes were seen in the incidence rate during the study period. For age groups, a trend of stepwise increase in the incidence rate of IE was observed for increasing age groups, however no temporal changes were observed (Figure 2).

Conclusion

The incidence of IE following prosthetic heart valve implantation has increased slightly over the last 20 years in Denmark.

Funding Acknowledgement

Type of funding sources: None.

Socioeconomic position and initiation of SGLT-2 inhibitors or GLP-1 receptor agonists in patients with type 2 diabetes – a Danish nationwide observational study

Background

Between 2015 and 2017, Sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucacon-like-peptide-1 receptor agonists (GLP-1 RA) were shown to reduce cardiovascular events in patients with type 2 diabetes and cardiovascular disease. Thus, in 2018, guidelines were updated to favor these drugs in patients with cardiovascular disease and type 2 diabetes. Lower socioeconomic position may adversely affect use of SGLT-2 inhibitors and GLP-1 RA.

Purpose

We aimed to examine socioeconomic differences in initiation of SGLT-2 inhibitors and GLP-1 RA in a contemporary population of patients with type 2 diabetes.

Methods

Through the Danish nationwide registers, we identified all patients with type 2 diabetes who initiated second-line add-on therapy after metformin monotherapy between December 10, 2012, and December 31, 2018. Patients aged 40–79 years and without a history of end-stage renal disease were included. We measured socioeconomic position according to level of income: Low = 1st quartile; Middle = 2nd and 3rd quartile; High = 4th quartile. Based on multivariable logistic regression models adjusted for age, sex, cohabitation status, duration of type 2 diabetes, comorbidities, and cardiovascular medications, we reported the standardised probabilities of initiating each drug class at time of first intensification according to income group and time period: 2012–2014, 2015–2017, and 2018.

Results

The 33,201 patients had a median age of 63 years (interquartile range 53–69). The probability of initiating a SGLT-2 inhibitor or a GLP-1 RA increased over time in all income-groups. In each time period, the standardised probability of initiating a SGLT-2 inhibitor or a GLP-1 RA at time of first intensification increased with increasing income (Figure): in 2012–2014, from 9.6% (95% confidence interval (CI) 8.4–10.9) in the lowest income group to 14.4% (CI 12.9–15.9) in the highest income group; in 2015–2017, from 19.5% (CI 18.3–20.7) to 24.6% (CI 23.3–25.9); in 2018, from 39.9% (CI 37.5–42.3) to 50.7% (CI 48.2–53.1). The absolute difference between high and low income groups increased over time, reaching 10.8% (CI 7.3–14.3) in 2018. A similar trend was observed in both subgroups of patients with and without established cardiovascular disease (data not shown). Initiation of a dipeptidyl peptidase-4 (DPP-4) inhibitor increased with income in the early time periods, but this trend reversed in 2018 (Figure). Initiation of sulfonylureas (SU) showed a consistent inverse association with income in each time period.

Conclusions

Low socioeconomic position was consistently associated with a lower probability of initiation of a GLP-1 RA or a SLGT-2 inhibitor at time of first intensification of antidiabetic treatment, even after guidelines recommended these drugs to patients with established cardiovascular disease. These disparities may adversely affect cardiovascular outcomes in patients with low socioeconomic position.

Funding Acknowledgement

Type of funding sources: None.

Independent risk factors of mortality in streptococcal infective endocarditis

Background

Streptococcal bloodstream infection (BSI) is a common cause of infective endocarditis (IE), yet prognostic factors for mortality are poorly investigated.

Purpose

To investigate risk factors associated with in-hospital and one-year mortality in streptococcal IE.

Methods

All patients with a streptococcal BSI, from 2008 to 2017, were included in a regional population-based setup. Based on microbiological identification of phylogenetic relationship, streptococcal species were classified into eight main subgroups: Anginosus, Bovis, Mitis, Mutans, Salivarius, Pyogenic, nutritionally variant streptococci, and S. pneumoniae. Data were crosslinked with nationwide registries for identification of demographics, concomitant hospitalization with IE, medical history, seasonal variation, and socioeconomic status. Patients were followed up until death or a maximum of 365 days after admittance, whichever came first. Using a multivariable adjusted Cox proportional hazard analysis, independent risk factors associated with in-hospital and one-year mortality were identified.

Results

Among 6,224 patients with a streptococcal BSI, 435 (7.0%) patients with streptococcal IE (mean age 69.0 (SD 14.8), 66% men) were included. The in-hospital mortality in IE patients was 11% (n=48), while the one-year mortality was 23% (n=100). Patients infected with species from the Bovis group had the lowest crude one-year mortality (13%), while patients infected with the Salivarius group had the highest crude mortality (36%). The proportion of deaths among women with IE were significantly higher than among men, both in-hospital (15% versus 9%, p=0.04) and after one year (29% versus 20%, p=0.02). Further, patients dying within one year had a significantly higher prevalence of ischemic heart disease (IHD) (p=0.02), congestive heart failure (CHF) (p<0.0001), cerebral vascular disease (CVD) (p=0.004), cancer (p=0.04), chronic obstructive pulmonary disease (COPD) (p=0.01), and renal disease (p=0.01) than survivors. In the adjusted analysis, age (Hazard Ratio (HR) 1.03, p=0.036) and renal disease (HR 2.46, p=0.045) were associated with higher in-hospital mortality. Furthermore, three independent significant factors associated with one-year mortality were identified; CHF (HR 2.18 [95% confidence interval (CI) 1.30–3.63]), cancer (HR 1.95 [95% CI 1.01–3.77]), and age (HR 1.03 [95% CI 1.01–1.05]) (Figure 1). However, patients infected with species from the Bovis group, had significantly lower risk of death at one-year (HR 0.30 [95% CI 0.10–0.89]) (Figure 1).

Conclusion

Having a renal disease at the time of IE diagnosis was associated with a higher in-hospital mortality in patients with streptococcal infective endocarditis. Further, congestive heart failure and cancer were associated with a higher one-year mortality, while the Bovis group was associated with a lower one-year mortality.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Zealand University Hospital Roskilde and Helsefonden (20-B-0340) Figure 1. Adjusted risk of one-year mortality

Risk of infective endocarditis in patients with Staphylococcus aureus blood stream infection and declining kidney function

Background

Worldwide, Staphylococcus aureus (S.aureus) is one the most common causes of infective endocarditis (IE), particularly in dialysis patients. However, the association between mildly and moderately decreased kidney function and IE in patients with S.aureus blood stream infection (SAB) has not been examined.

Purpose

In a retrospective nation-wide study, to evaluate the association between IE and declining kidney function in SAB patients.

Methods

All patients with first-time SAB between January 1st, 1996 to December 31st, 2018 were identified from a national database including >90% of all patients with SAB. By cross-linking with other nationwide databases, co-morbidities were recorded. The population was divided into 4 groups according to eGFR: group 1 (eGFR ≥90), group 2 (eGFR 30–89), group 3 (eGFR <30) and group 4 (Renal Replacement Therapy dependent). Patients were followed until the outcome of IE. Changes in co-morbidities across the eGFR groups were tested with the Cochran-Armitage test. In a multivariable logistic regression analysis, the odds ratio (OR) of IE was calculated for each eGFR group while adjusting for age, sex, hypertension, diabetes, native valve disease (NVD), prosthetic valve, and cardiac implantable electronic device (CIED).

Results

Among 17,759 SAB patients, 1,098 were diagnosed with IE. The male population accounted for 60–70% of the IE patients in each eGFR group (Table 1). The overall median age of S.aureus IE patients was 61.5 [48–72] with the highest median age in group 2 (67 [57–76]). Across the eGFR groups, there was a significant increase in the prevalence of diabetes (12.6% in group 1 to 47.0% in group 4), hypertension (18.9% in group 1 to 80% in group 4) and native valve disease (18.7% in group 1 to 36.4% in group 4), p<0.0001. In a multivariate analysis with group 1 as reference, the adjusted OR of S.aureus IE increased significantly with OR 1.16 [95% CI 1.01–1.34] in group 2 to OR 1.42 [95% CI 1.07–1.87] in group 3. The increase was not significant in group 4, OR 1.63 [95% CI 0.95–2.53]. The OR of S.aureus IE decreased with increasing age groups and OR was 0.55 [95% CI 0.43–0.71] among patients >80 years as compared to the reference age group, 18–39 years. A significantly increased OR of S.aureus IE was found among patients with NVD (OR 3.25 [95% CI 2.22–4.76]), prosthetic valve (OR 6.31 [95% CI 5.10–7.79] and CIED (OR 2.88 [95% CI 2.35–3.53]). The overall in-hospital mortality was 16.4% (n=181), with the highest mortality in group 3 (n=11, 22.3%). Overall, the one-year mortality was 26.6% (n=292), and the highest mortality was found in group 4 (n=29, 34.1%). When adjusting for age and sex, mortality did not differ significantly with declining eGFR.

Conclusion

In this study, we found a significant increase in the odds ratio of IE in patients with SAB when kidney function decreased. Both in-hospital and one-year mortality were high, but did not differ significantly across the eGFR groups.

Funding Acknowledgement

Type of funding sources: None.

Valve phenotype and likelihood of surgery in patients with bicuspid aortic valve

Background

It is well established, that patients with bicuspid aortic valve (BAV) are at increased risk of developing severe aortic valve and/or aortic disease early in life. Knowledge of factors placing patients at risk of early surgery is therefore essential. Several studies have found associations between aortic valve phenotype, aortopaty and type of valve dysfunction.

Purpose

To characterize the valve phenotype associated with increased likelihood of early surgery of the aortic valve and aorta in a large cohort of BAV patients.

Methods

A retrospective study of adult BAV patients seen in the outpatient clinics at two hospitals in Denmark from 2006 until May 2020. Clinical and anatomical data were obtained retrospectively from electronic health charts and hospital echocardiography databases. Bicuspid valve morphology was classified according to Sievers Classification; no raphe (Type 0), one raphe (Type 1 with fusion of the right-noncoronary cusps (R/N), Left-noncoronary cusp fusion (L/N) and Left-right coronary cusp fusion (L/R)) or 2 raphes (Type 2). Likelihood of surgery was calculated using odds ratio (OR). We performed multivariate regression models to adjust for potential confounding by sex, age, coarctatio aorta, aortic dilatation and cardiovascular risk factors.

Results

A total 983 BAV patients were identified of whom 877 had an available baseline echocardiography and were included. Clinical and echocardiographic characteristics are seen in Table 1. Noteworthy is that Type 2 patients had significantly higher occurrence of moderate-severe aortic regurgitation when compared to the whole population (38.9% vs 18.3%, p<0.01).

During the study period 305 patients (34.8%) underwent surgery. Median age at time of surgery was 62 (IQR 55; 69) years. Using the most common phenotype (Type 1 L/R fusion) as a reference, patients with Type 0 had a lower likelihood of surgery (unadjusted OR 0.58, 95% CI: 0.39–0.85), while patients with Type 2 had a significantly higher likelihood of surgery (OR 2.76, 95% CI: 1.05–7.23). In a multiple regression analysis, adjusting for age, sex, coarctatio aorta and aortic dilatation did not change the primary finding of association between BAV phenotype and OR for surgery. Likelihood of surgery was lower for women (OR 0.66, 95% CI: 0.46–0.96) and increased with age. Further adjustments for cardiovascular risk factors (mentioned in Table 1) did not change the results. Median age at time of surgery was younger for patients with Type 2 (59 years, IQR 44; 65).

Indications for valve surgery are shown in Table 2.

Conclusion

In this study we found significant association between valve phenotype and likelihood of surgery of the valve or aorta in patients with bicuspid aortic valve. Using BAV Type 1 L/R as reference, likelihood of surgery was lower in patients with BAV type 0, and higher in patients with BAV type 2. Results were consistent after adjustment for confounders in multivariate analyses.

Funding Acknowledgement

Type of funding sources: None.

Inflammatory risk factors are not associated with coronary artery calcification in patients with myeloproliferative philadelphia-negative neoplasms

Background

Myeloproliferative Philadelphia-negative Neoplasms (MPNs) are hematological cancers associated with chronic inflammation and endothelial dysfunction, conditions that may lead to development of premature atherosclerosis.

Purpose

To investigate whether biomarkers of inflammation and endothelial dysfunction are associated with the degree of atherosclerotic burden, measured by Coronary Artery Calcium Score (CACS), in patients with MPNs.

Methods

Patients with a validated MPN diagnosis; essential thrombocythemia (ET), polycythemia vera (PV) or myelofibrosis (MF), were recruited between 2016 and 2018 from one single specialized hematologic center. Patients filled out a standardized questionnaire on medical history, current medication, alcohol and smoking habits and family medical history. They were examined by cardiac computed tomography (CT), Endothelial Peripheral Arterial Tone (EndoPAT), and a range of blood analyses. The atherosclerotic burden was evaluated by CACS. High sensitivity C-reactive protein (hs-CRP) and Neutrophil:Lymphocyt Ratio (NLR) were used as indicators of chronic inflammation. EndoPAT was applied to evaluate endothelial dysfunction, which is linked to development of atherosclerosis. The JAK2V617F-mutation is a common gene mutation in MPN-patients. It affects the gene coding the Janus kinase 2 (JAK2) protein, and can be detected by qPCR of peripheral blood or bone marrow. The JAK2V617F-mutation is a risk factor associated with both chronic inflammation and endothelial dysfunction. Multivariable logistic regression analyses were used to identify associations between potential risk factors and a higher CACS value.

Results

Among 170 included patients, 161 patients completed cardiac CT (mean age 65.5 (SD 10.5), 52% men). Baseline data is presented in Table 1. JAK2V617F-mutation was found in 137 (85%) patients, 53 patients (35%, n=152) had hs-CRP>2.0 mg/L, 107 (67%, n=160) had NLR>2.15 and 32 (21%, n=154) had an abnormal EndoPAT. Overall, 66 patients (41%) had a CACS>100, with no significant difference between ET (41%), PV (42%) and MF (50%) (p=0.3). In patients with a history of ischemic heart disease (IHD), 92% had CACS>100, compared to 37% in patients without prior IHD (p=0.0003).

Five independent factors associated with a CACS>100 were identified; age (OR: 1.3 [95% CI 1.1–1.4]), male sex (OR: 15.2 [95% CI 4.0–57.7]), prior IHD (OR: 15.9 [95% CI 1.2–202.4]), smoking (OR: 3.3 [95% CI 1.1–10.1]), and abnormal EndoPAT (OR: 4.8 [95% CI 1.1–20.0]) (Figure 1). Hs-CRP, NLR and JAK2V617F-mutation status were not significantly associated with CACS >100.

Conclusion

In this cohort of patients with MPNs, markers of chronic inflammation like hs-CRP and NLR were not associated with higher CACS, nor was the JAK2V617F-mutation. Traditional risk factors of cardiovascular disease seem to be sufficient to identify MPN patients with increased atherosclerotic burden, but measuring endothelial dysfunction provides additional information.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Department of Cardiology, Zealand University Hospital, Region Zealand, Denmark Table 1. Baseline characteristicsFigure 1. Odds ratio for CACS >100

Age differences in mortality in patients undergoing surgery for infective endocarditis

Background

Infective endocarditis (IE) is associated with high mortality. Surgery may improve survival, but the intercept between benefit and harm is hard to balance and may be closely related to age.

Purpose

To examine the in-hospital and 90-day mortality in patients undergoing surgery for IE and to identify differences between age groups and type of valvular intervention.

Methods

By crosslinking nationwide Danish registries we identified patients with first-time IE undergoing surgical treatment in the period from 2000 to 2017. The study population was grouped in patients <60 years, 60–75 years, and ≥75 years of age. High-risk subgroups by age and surgical valve intervention (mitral vs aortic vs mitral+aortic) during IE admission were examined. Kaplan Meier estimates was used to identify 90-day mortality by age groups and multivariable adjusted Cox proportional hazard analysis was used to examine factors associated with 90-day mortality.

Results

We included 1,767 patients with IE undergoing surgery, 735 patients <60 years (24.1% female), 766 patients 60–75 years (25.8% female), and 266 patients >75 years (36.1% female). The proportion of patients with IE undergoing surgery was 35.3%, 26.9%, and 9.1% for patients <60 years, 60–75 years, and >75 years, respectively. For patients with IE undergoing surgery, the in-hospital mortality was 6.4%, 13.6%, and 20.3% for patients <60 years, 60–75 years, and ≥75 years of age, respectively and mortality at 90 days were 7.5%, 13.9%, and 22.3%, respectively. Factors associated with an increased risk 90-day mortality were: mitral valve surgery and a combination of mitral and aortic valve surgery as compared with isolated aortic valve surgery, patients 60–75 years and >75 years as compared with patients aged <60 years, prosthetic heart valve prior to IE admission, and diabetes, Figure. Patients >75 years undergoing a combination of mitral and aortic valve surgery had an in-hospital mortality of 36.3%.

Conclusion

In patients undergoing surgery for IE, a stepwise increase in 90-day mortality was seen for age groups, highest among patients >75 years with a 90-day mortality of more than 20%. Patients undergoing mitral and combined mitral and aortic valve surgery as compared to isolated aortic valve surgery were associated with a higher mortality. These findings may be of importance for the management strategy of patients with IE.

Mortality risk

Funding Acknowledgement

Type of funding source: None

P3661Two-fold increase in incidence of infective endocarditis in the period 1997–2016: a Danish nationwide study

Background

Infective Endocarditis (IE) is a disease with high mortality. Previous studies have shown considerable differences and contradicting trends in overall incidence and mortality why data from an unselected nationwide cohort is needed.

Purpose

We investigated temporal trends in the incidence rate and in-hospital mortality of IE in Denmark in the period of 1997–2016.

Methods

We included cases of first-time IE (1997–2016) using Danish nationwide registries. Crude incidence rates were given for each calendar year. Further, incidence rates were reported for subgroups of age and sex. For the analysis of patient characteristics and in-hospital mortality, the study cohort was grouped into four 5-year intervals (1997–2001, 2002–2006, 2007–2011, 2012–2016). Multivariable adjusted Cox proportional hazard model was used to compare in-hospital mortality between groups.

Results

A total of 8,147 patients with IE were identified in the period of 1997–2016. The median age and proportion of males increased from 64.3 years (P25-P75: 48–75.5) and 59.1% to 71.8 years (P25-P75: 62.1–79.9) and 67.1% in 1997–2001 and 2012–2016, respectively. The overall incidence rate (Figure 1) increased from 4.68/100.000-person-years (PY) (CI95: 4.17–5.26) to 8.23/100.000 PY (CI95: 7.53–8.99) in 1997 and 2016, respectively. Male incidence increased from 5.35/100.000 PY (CI95: 4.59–6.23) to 11.03/100.000 PY (CI95: 9.9–12.29) and female incidence increased from 4.03/100.000 PY (CI95: 3.38–4.8) to 5.44/100.000 PY (CI95: 4.67–6.35) in 1997 and 2016 respectively. Incidence rates increased more than seven-fold for the oldest age group (≥80 years) from 1997 to 2016 (6.95/100.000 PY [CI95: 5.32–9.08] to 51.19/100.000 PY [CI95: 43.41–60.38], respectively). In-hospital mortality was significantly lower for patients with IE in the period of 2011–2016 compared with 1997–2001 HR: 0.8 (CI95: 0.69–0.92).

Figure 1

Conclusion

Infective endocarditis incidences are increasing mostly among men and elderly patients. In order to prevent this disease as best as possible, we need more knowledge on causes for this increasing incidence.

P3665Prevalence of infective endocarditis in patients with positive blood cultures: a Danish nationwide study

Background

Increasing attention has been given to the risk of infective endocarditis (IE) in patients with certain blood stream infections (BSI). Previous studies have been conducted on selected patient cohorts, yet unselected data are sparse.

Purpose

To investigate the nationwide prevalence of diagnosed IE in BSIs with bacteria typically associated with IE.

Methods

By crosslinking nationwide registries from 2010–2016, we identified patients with BSIs typically associated with IE: Enterococcus faecalis, Staphylococcus, Streptococcus spp., and coagulase negative staphylococci (CoNS) and examined the concurrent IE prevalence. A trend test was used to examine temporal changes in the prevalence of IE.

Results

In total 60,119 BSIs, distributed with 15,407, 16,790, and 27,922 BSIs were identified in the periods of 2010–2011, 2012–2013, and 2014–2016, respectively.

Patients with E. Faecalis had the highest prevalence of diagnosed IE (16.3%) followed by S. aureus (10.2%), Streptococcus spp. (7.3%), and CoNS (1.6%) (Figure). During the study period, the prevalence of IE among patients with E. faecalis increased significantly (p=0.003), Male patients had higher prevalence of IE for all microorganisms investigated compared with females. A significant increase in the prevalence of IE was seen for E. faecalis, Streptococcus spp., and CoNS with increasing age.

Percent with endocarditis

Conclusion

For E. faecalis BSI, 1 in 6 had IE, for S. aureus BSI 1 in 10 had IE, and for Streptococcus spp. 1 in 14 had IE. Our results support screening for IE in patients with E. faecalis, S. aureus, or Streptococcus spp. BSI in order to offer appropriate therapy.

P2756Risk of stroke subsequent to infective endocarditis: a nationwide study

Background

Patients with infective endocarditis (IE) are at high risk of cerebral embolization, however little is known about the risk of stroke subsequent to IE in patients with stroke during IE admission.

Purpose

To investigate the risk of stroke after discharge of IE in patients with stroke during IE admission compared with patients without stroke during IE admission.

Methods

Using Danish nationwide registries we identified non-surgically treated patients with IE discharged alive, in the period 1996–2016. The study population was grouped in 1) patients with stroke during IE admission and 2) patients without stroke during IE admission. Crude cumulative risk of stoke were calculated using the Aalen-Johansen estimator accounting for death as a competing risk. Multivariable adjusted Cox proportional hazard analysis was used to compare the associated risk of stroke between groups. We identified differentials in the associated risk of stroke during follow-up between groups (p=0.006 for interaction with time), and follow-up was split into 0–1 year and 1–5 years time periods.

Results

We identified 4,284 patients with IE, 239 patients (5.6%) with stroke during IE admission (median age: 71.9 years, 58.2% males), and 4,045 patients (94.4%) without stroke during IE admission (median age 69.7 years, 64.8% males). The crude cumulative risk of stroke within 1 year of follow-up is shown in Figure Panel A, and with 1 to 5 years of follow-up in Figure Panel B. In multivariable adjusted analyses, the associated risk of stroke was higher in patients with stroke during IE admission within a follow-up period of 1 year, HR 3.21 (95% CI: 1.66–6.20) compared with patients without stroke during IE admission. From 1 to 5 years of follow-up, we identified no difference in the associated risk of stroke between groups, HR 0.91 (95% CI: 0.33–2.50).

Cumulative incidence of stroke

Conclusion

Non-surgically treated patients with IE who had a stroke during IE admission were at significantly higher associated risk of subsequent stroke – although not significant beyond 1 year after discharge from IE. These findings underline the need for identification of causes and mechanisms of recurrent strokes after IE to develop preventive means.

P2762Recurrent infective endocarditis versus first-time infective endocarditis after heart valve surgery

Introduction

Infective endocarditis (IE) may require heart valve surgery. However, it is well-known that heart valve surgery itself and previous IE predispose to IE.

Purpose

To access the risk of recurrent IE compared with first-time IE following heart valve surgery.

Methods

Using Danish nationwide registries, patients undergoing left-sided heart valve surgery (i.e. valve replacement or repair) in the course of a first-time IE hospitalization (1996–2017) were identified and matched with patients undergoing left-sided heart valve surgery due to another cause than IE in a 1:1 ratio. Patients were stratified according to type of surgical valve intervention and affected valve. The comparative risk of IE was assessed by cumulative incidence curves and multivariable Cox regression analyses.

Results

The study population comprised 975 patients with a first-time admission for left-sided IE requiring heart valve surgery (median age, 64.3 years [interquartile range 55.7–72.1], 77.6% men) matched with 975 controls undergoing left-sided heart valve surgery due to other causes than IE. The risk of recurrent IE was significantly higher than the risk of first-time IE following heart valve surgery (5.5% and 3.1% by 10 years, hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.07–2.78) (Figure 1). The risk of IE recurrence was not significantly different in patients with IE undergoing valve replacement versus valve repair (5.6% and 5.4% respectively, HR 1.76, 95% CI 0.79–3.05). Likewise, the risk of IE recurrence was not significantly different for mitral versus aortic valve patients (3.5% and 6.3%, respectively, HR 0.73, 95% CI 0.36–1.48). Yet, the risk of IE recurrence was significantly higher among IE patients with biological versus mechanical prostheses (6.4% and 4.6%, respectively, HR 2.20, 95% CI 1.13–4.31).

Figure 1: Cumulative incidences

Conclusion

Following left-sided heart valve surgery, the associated risk of recurrent IE was significantly higher than the risk of first-time IE.

Acknowledgement/Funding

None

P4533Duration of heart failure and effect of defibrillator implantation in patients with non-ischemic systolic heart failure

Introduction

Patients with non-ischemic systolic heart failure have increased risk of sudden cardiac death (SCD) and death from progressive pump failure. Whether the risk of SCD changes over time is unknown. We seek to investigate the relationship between duration of heart failure, mode of death, and effect of implantable cardioverter defibrillator (ICD) implantation.

Methods

We examined the risk of all-cause death and SCD according to the duration of heart failure among patients with non-ischemic systolic heart failure enrolled in the Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality (DANISH) trial. Patients were divided according to quartiles of heart failure duration (Q1 ≤8 months, Q2 9 ≤18 months, Q3 19 ≤65 months, Q4 ≥66 months).

Results

A total number of 1116 patients were included. Patients with the longest duration of heart failure were older, more often men, had more comorbidity, and more often received cardiac resynchronizing therapy device. Doubling of heart failure duration was an independent predictor of both all-cause mortality (HR 1.26 95% CI 1.17–1.37, p<0.0001), and SCD (HR 1.29 95% CI 1.11–1.49, p=0.0009). The proportion of deaths caused by SCD was not different between heart failure quartiles (p=0.91), and the effect of ICD implantation on all-cause mortality was not modified by the duration of heart failure (p=0.59).

Duration of heart failure and death

Conclusions

Duration of heart failure predicted both all-cause mortality and risk of SCD independently of other risk indicators. However, the proportion of death caused by SCD did not change with longer duration of heart failure and the effect of ICD was not modified by the duration of heart failure.

Acknowledgement/Funding

The work was sponsored by The Danish Heart Foundation (Hjerteforeningen) and the Lundbeck Foundation (Lundbeckfonden). The DANISH trial was supported

P2754Streptococcal infective endocarditis: distribution of species and their prognosis

Background

Infective endocarditis (IE) is frequently caused by streptococcal species. However, there is limited knowledge about the relationship between different streptococcal species and IE, and their associated outcomes.

Purpose

To examine the prevalence of streptococci at species level in IE, and to relate these different species to outcomes.

Methods

From 2002–2012 we prospectively collected consecutive patients with IE admitted to two tertiary heart centres covering a catchment area of 2.4 million people. The registry comprises 915 IE patients, 366 (40%) with streptococcal IE. Based on phylogenetic relationship, streptococcal species were classified into seven main groups: Mitis, Bovis, Mutans, Anginosus, Salivarius, Pyogenic and Nutritionally Variant Streptococcus (NVS). Classification at species level was not possible in 51 patients, who were excluded. Complications and prognosis of streptococcal IE were compared between the subgroups, and at species level.

Results

We included 315 patients with streptococcal IE. Mean age was 63 (IQR 52–76) years, and most were men (67%). A total of 115 patients (37%) had a previous heart valve disease, 58 (18%) had a prosthetic valve, 22 (7%) had previously had IE and 29 (9%) had a cardiac electronic device. With 148 episodes (47%) the Mitis group was the most common cause of IE. Other frequent groups were the Pyogenic group and the Bovis group, accounting for 66 (21%) and 51 (16%) of the cases, respectively. Surgery was carried out in 55% (n=173) of all cases. Patients infected with S. pneumoniae or S. agalactiae had a significantly higher rate of surgery, 72.2% (n=13) and 71.9% (n=23) respectively, whereas the Bovis group had a significantly lower rate, 35.5% (n=18) (p=0.048). The aortic valve was infected in 137 patients (43.5%), mitral valve in 105 patients (33.3%) and both valves were infected in 53 patients (16.8%). Twenty patients (6.3%) had right-sided IE, including pacemaker lead IE. There was no significant difference between the species subgroups regarding type of infected valve. Embolization and osteitis were observed in 76 (24.1%) and 30 (9.5%) patients, respectively. There was no significant difference between the species groups, as was the case with mortality: 23 patients (7.3%) died in-hospital and the one-year mortality was 16% (n=50).

Distribution of streptococcal IE

Conclusion

Species of the Mitis group were the most frequent Streptococci causing IE. Patients infected with S. pneumonia or S. agalactiae had significantly higher rate of surgery, and patients infected with S. bovis group had lower rate of surgery. There was no significant difference in rate of complications such as abscesses, embolization, osteitis or mortality between the streptococcal species.

Acknowledgement/Funding

Supported by grants from Herlev-Gentofte University Hospital Research Foundation

Incidence, clinical characteristics and 30-day mortality of enterococcal bacteraemia in Denmark 2006-2009: a population-based cohort study

Enterococci currently account for approximately 10% of all bacteraemias, reflecting remarkable changes in their epidemiology. However, population-based data of enterococcal bacteraemia are scarce. A population-based cohort study comprised all patients with a first episode of Enterococcus faecalis or Enterococcus faecium bacteraemia in two Danish regions during 2006-2009. We used data collected prospectively during clinical microbiological counselling and hospital registry data. We determined the incidence of mono- and polymicrobial bacteraemia and assessed clinical and microbiological characteristics as predictors of 30-day mortality in monomicrobial bacteraemia by logistic regression analysis. We identified 1145 bacteraemic patients, 700 (61%) of whom had monomicrobial bacteraemia. The incidence was 19.6/100 000 person-years (13.0/100 000 person-years for E. faecalis and 6.6/100 000 person-years for E. faecium). The majority of bacteraemias were hospital-acquired (E. faecalis, 45.7%; E. faecium, 85.2%). Urinary tract and intra-abdominal infections were the predominant foci for the two species, respectively. Infective endocarditis (IE) accounted for 25% of patients with community-acquired E. faecalis bacteraemia. Thirty-day mortality was 21.4% in patients with E. faecalis and 34.6% in patients with E. faecium. Predictors of 30-day mortality included age, co-morbidity and hospital-acquired bacteraemia. In addition, intra-abdominal infection, unknown focus and high-level gentamicin resistance were predictors of mortality in E. faecalis patients. E. faecium was associated with increased risk of mortality compared with E. faecalis. The study emphasizes the importance of enterococci both in terms of incidence and prognosis. The frequency of IE in patients with E. faecalis bacteraemia emphasizes the importance of echocardiography, especially in community-acquired cases.

Warfarin therapy and incidence of cerebrovascular complications in left-sided native valve endocarditis

Anticoagulant therapy has been anticipated to increase the risk of cerebrovascular complications (CVC) in native valve endocarditis (NVE). This study investigates the relationship between ongoing oral anticoagulant therapy and the incidence of symptomatic CVC in left-sided NVE. In a prospective cohort study, the CVC incidence was compared between NVE patients with and without ongoing warfarin. Among 587 NVE episodes, 48 (8%) occurred in patients on warfarin. A symptomatic CVC was seen in 144 (25%) patients, with only three on warfarin. CVC were significantly less frequent in patients on warfarin (6% vs. 26%, odds ratio [OR] 0.20, 95% confidence interval [CI] 0.06-0.6, p = 0.006). No increase in haemorrhagic lesions was detected in patients on warfarin. Staphylococcus aureus aetiology (adjusted OR [aOR] 6.3, 95% CI 3.8-10.4) and vegetation length (aOR 1.04, 96% CI 1.01-1.07) were risk factors for CVC, while warfarin on admission (aOR 0.26, 95% CI 0.07-0.94), history of congestive heart failure (adjusted OR 0.22, 95% CI 0.1-0.52) and previous endocarditis (aOR 0.1, 95% CI 0.01-0.79) correlated with lower CVC frequency.

Radioimmunoassay of Endothelin in Human Plasma

A specific and sensitive radioimmunoassay (RIA) for determination of endothelin-1 (ET-1) in human plasma has been developed. Antibodies were raised in rabbits using synthetic ET-1 conjugated to thyroglobulin as immunogen. The antibodies obtained were used at a final dilution of 1:300,000 yielding maximum binding of 61.7 +/- 3.0% (mean +/- 1 SD, n = 20) of 125I-ET-1. The ID50 (inhibitory dose 50%) was 4.5 +/- 0.6 fmol/100 microliters (mean +/- 1 SD, n = 20). The sensitivity of the RIA was 0.33 fmol/100 microliters standard solution. No cross reactivity was observed with endothelin-3, big-endothelin-1, atrial natriuretic factor, angiotensin I or angiotensin II. The cross-reactivity with endothelin-2 was 100%. Endothelin was extracted from acidified plasma with Sep-pak C18 cartridges and recovery of ET-1 added to normal plasma was 70.9 +/- 10.3% (mean +/- 1 SD, n = 12). The concentration of ET-1 in plasma from normal subjects was 1.5 +/- 0.4 pmol/l (mean +/- 1 SD, n = 11) ranging from 1.0 to 2.2 pmol/1. Extracts of normal human plasma subjected to high performance liquid chromatography on a reverse phase C18 column showed one peak of immunoreactivity co-eluting with the standard for ET-1. From these data it is concluded that the immunoreactive material measured in normal plasma with the present RIA is identical to ET-1.

Normal responses of atrial natriuretic factor and renal tubular function to sodium loading in hypertension-prone humans

BACKGROUND

In order to explore the hypothesis of an atrial natriuretic factor (ANF) deficiency in prehypertension, we compared the response to sodium loading on ANF and renal function in subjects with positive and negative histories of hypertension.

METHODS

Twenty-two offspring of hypertensive parents (OH) and 20 offspring of normotensive parents (ON) were studied after 4 days of low (50 mmol/day) or high (300 mmol/day) dietary sodium intake. The diets were allocated randomly. Blood pressure (BP), renal function, plasma concentration of ANF, cyclic guanosine monophosphate (cGMP), renin, angiotensin I and II, aldosterone, endothelin and catecholamines were determined during a clearance period of 90 min on both diets. Neurohormones were measured by radioimmunoassays. Renal function was determined by simultaneous measurements of 51Cr-ethylenediaminetetraacetate (a marker of glomerular filtration rate), lithium and sodium clearances.

RESULTS

Supine systolic and diastolic BPs were significantly elevated in OH, with both low and high dietary sodium intake. There was no difference in ANF and cGMP concentrations on the low sodium diet. Increasing sodium intake caused a similar increase in ANF in OH and ON but cGMP did not change significantly. As expected the activity of the renin-angiotensin-aldosterone system was decreased by enhancing sodium intake but with both low and high sodium intake plasma renin concentration was significantly higher in OH than in ON. Activation of the sympathetic nervous system with low sodium intake was indicated by a moderate increase in plasma concentrations of epinephrine and norepinephrine in both groups. The renal effects were characterized by significant increases in GFR, lithium and sodium clearances with increasing sodium intake. There were no differences between OH and ON. Estimated values of fractional proximal and distal tubular sodium reabsorption decreased significantly and in a similar way in both OH and ON.

CONCLUSION

These results indicate that the renal and neuroendocrine responses to dietary sodium loading are similar in both OH and ON. The only difference was a higher BP and an elevated plasma renin concentration on both dietary regimens in OH compared with ON. In particular, in OH and ON an identical increase in plasma ANF concentration in response to sodium loading was found. Thus, this study cannot support the hypothesis of a dysregulation of ANF in hypertension-prone humans.

Renal effects of hyperinsulinaemia in subjects with two hypertensive parents

The aim of this investigation was to study the effects of isoglycaemic hyperinsulinaemia on the renal metabolism of electrolytes and water in subjects with a strong genetic predisposition to essential hypertension, compared with that in non-predisposed subjects. We studied 25 normotensive subjects aged 18-35 years whose parents both had essential hypertension, and 22 age- and sex-matched subjects whose parents were both normotensive. Diabetes or morbid obesity in any subject or parent excluded the family. The 24-h blood pressure was measured. The subjects received an isocaloric diet with a fixed content of sodium and potassium for 4 days before the study. An isoglycaemic, hyperinsulinaemic clamp with infusion of insulin (40 munits.min(-1).m(-2)) was performed. We measured the renal clearance of diethylenetriaminepenta-acetic acid, sodium, potassium and lithium both under basal conditions and during hyperinsulinaemia. In response to hyperinsulinaemia, renal sodium clearance decreased to a significantly greater extent in the hypertension-prone subjects [0.57 (0.74, 0.36) ml.min(-1).1.73 m(2) (median and quartiles)] than in the controls [0.34 (0.56, 0.18) ml. min(-1).1.73 m(2)] (P=0.04). Compared with the controls, the subjects predisposed to hypertension had a higher 24-h diastolic blood pressure [78 (70, 82) mmHg, compared with 73 (68, 77) mmHg], but a similar insulin sensitivity index ¿10(7)x[313 (225, 427)] compared with 10(7)x[354 (218, 435)] l(2).min(-1).pmol(-1).kg(-1)¿. Thus the sodium-retaining effect of insulin was more pronounced in subjects with a strong genetic predisposition to essential hypertension than in subjects with normotensive parents. This effect may contribute to the development of hypertension in subjects with a genetic predisposition to hypertension.

Insulin resistance, exercise capacity and body composition in subjects with two hypertensive parents

OBJECTIVE

To study insulin resistance in subjects with strong genetic predisposition to essential hypertension, compared with non-disposed subjects.

SUBJECTS

Thirty normotensive subjects aged 18-35 years whose parents both had essential hypertension, and 30 age- and sex matched subjects whose parents were both normotensive, were studied. Subjects or parents with diabetes and morbid obesity were excluded.

METHODS

The study comprised (1) a frequent sampling oral glucose tolerance test; (2) an isoglycemic hyperinsulinemic clamp study; (3) an analysis of body composition by dual-energy X-ray absorptiometry; (4) an exercise test with gas exchange analysis; and (5) investigation of composition of usual diet by diet registration for 5 days.

RESULTS

The 24-h diastolic blood pressure was higher in subjects predisposed to hypertension compared with the controls: 78.1 versus 74.0 mmHg (confidence interval for the difference between the means; -0.5; -7.9), but the insulin sensitivity index was similar: 312 versus 362 I(2) min(-1) pmol(-1) kg(-1) (28; -129). The two groups were similar in terms of body composition, exercise capacity and composition of usual diet. Resting and 24-h diastolic blood pressures were correlated to abdominal fat mass but not to insulin sensitivity.

CONCLUSION

Subjects with a strong genetic predisposition to essential hypertension had increased diastolic blood pressure compared with subjects with normotensive parents, but they were not insulin resistant. This may be due to the subjects being highly selected as to confounding factors. The increased blood pressure in the hypertension prone subjects could not be attributed to differences in body composition, exercise capacity or dietary habits.

Renal sites of action of physiological increases in plasma atrial natriuretic factor concentration in essential hypertension

OBJECTIVES

To investigate the renal, haemodynamic and neurohormonal responses to low-dose infusions of atrial natriuretic factor (ANF) in hypertensive humans.

DESIGN

Ten patients with mild-to-moderate essential hypertension received incremental infusions of 3 and 6 ng/kg per min ANF or vehicle alone whilst on a constant dietary sodium intake. A 90-min basal clearance period was followed by two 2-h infusion periods, with urine collection in the last 90 min of each period. In each of the three clearance periods, glomerular filtration rate (GFR), renal tubular function, and the activity of the renin-angiotensin and sympathetic nervous systems were determined.

METHODS

The renal sites of ANF action were established by simultaneous measurements of 51Cr-ethylenediaminetetraacetate lithium and sodium clearances. Plasma concentrations of neurohormones were measured by radioimmunoassays.

RESULTS

Plasma ANF concentrations increased by 1.6- and 2.5-fold during the lower and higher ANF infusion rates, respectively. Plasma cyclic guanosine monophosphate concentrations increased in parallel. ANF caused no changes in supine systolic and diastolic blood pressure or in heart rate. In contrast, haematocrit values increased progressively across the study. The renal effects of ANF administration were characterized by an unaltered GFR and significant increases in the renal clearances of lithium (a marker of end-proximal fluid delivery) and sodium when compared with vehicle infusions, whereas urine flow did not change. Estimated values of fractional proximal and distal tubular sodium reabsorption decreased significantly. Plasma concentration of active renin decreased during ANF infusions, but no significant changes in plasma levels of renin substrate, angiotensin I, angiotensin II or aldosterone were observed. A subtle activation of the sympathetic nervous system was indicated by a moderate increase in plasma noradrenaline during the ANF infusions.

CONCLUSIONS

These results indicate that even small increases in plasma ANF, as can be found during physiological conditions, induce natriuresis in patients with essential hypertension by enhancing fluid delivery from the proximal tubules, in addition to impairing distal fractional sodium reabsorption. With minor exceptions, the ANF infusions caused qualitatively and quantitatively similar renal, haemodynamic and endocrine effects in the hypertensive patients as in a previously studied group of normotensive subjects.

Effects of hyperglycaemia on kidney function, atrial natriuretic factor and plasma renin in patients with insulin-dependent diabetes mellitus

In normoalbuminuric patients with insulin-dependent diabetes mellitus, plasma atrial natriuretic factor (ANF), cyclic GMP and active renin and the renal clearances of [99Tcm]-diethylenetriaminepentaacetic acid (DTPA) lithium and sodium were studied on a hyperglycaemia day and a euglycaemia day. Baseline euglycaemia was achieved by an overnight variable insulin infusion, which during study days was fixed at the rate necessary to maintain euglycaemia in the morning. After a baseline euglycaemic clearance period of 90 min, measurements were repeated in a new 90-min period beginning 150 min later. On the hyperglycaemia day i.v. infusion of 20% glucose was started at the end of the euglycaemic baseline period, increasing blood glucose (5.3 +/- 1.3 vs 12.1 +/- 1.2 mmol l-1, p less than 0.01). On the euglycaemia day blood glucose declined (5.1 +/- 1.0 vs 4.2 +/- 1.0 mmol l-1, p less than 0.02). Glomerular filtration rate (GFR) was unchanged by acute hyperglycaemia (127 +/- 16 vs 129 +/- 24 ml min-1, NS), but nearly normalized during maintained euglycaemia on the euglycaemia day (124 +/- 17 vs 105 +/- 16 ml min-1, p less than 0.01). When comparing the hyperglycaemic study period with the similarly timed period on the euglycaemia day, GFR was elevated by hyperglycaemia (129 +/- 24 vs 105 +/- 16 ml min-1, p less than 0.01), while the renal clearances of lithium and sodium were similar. Consequently, the calculated absolute proximal reabsorption rate of sodium and water was elevated during hyperglycaemia. Hyperglycaemia reduced the slight decline in plasma concentrations of ANF and cyclic GMP observed on the euglycaemia day. Active renin, glucagon and plasma osmolality were unchanged. In conclusion, marked changes in glomerular filtration rate are induced by changes in blood glucose concentration, but the effect is delayed and thus not directly related to renal tubular transport of glucose. Hyperglycaemia does not affect renal clearances of lithium and sodium, while proximal tubular reabsorption is markedly stimulated. These changes are not related to changes in ANF, renin, glucagon or plasma osmolality.

Comparison of different standards used in radioimmunoassay for atrial natriuretic factor (ANF)

Six different standards for determination of atrial natriuretic factor (ANF) in human plasma samples have been compared using our radio-immunoassay for ANF: International standard 85/669, National Biological Standard Boards, UK; Bachem standard, Torrance, USA; Bachem standard, Bubendorf, Switzerland; Bissendorf standard, Wedemark, Germany; Peninsula standard, Belmont, USA; UCB-Bioproducts standard, Brussels, Belgium. Standard curves obtained with different preparations were in parallel but showed considerable quantitative differences. Standard curves referring to the Bissendorf standard and the International standard, respectively, were almost identical. The dose required for 50% of binding inhibition (ID50s) determined with the Peninsula, UCB and Swiss Bachem standards were higher and ID50 for the American Bachem standard was much lower than ID50 for the International standard. In consequence, estimates of the ANF content in human plasma samples with different standard preparations as the reference showed a considerable variability. With the international standard as the gold reference (plasma ANF concentration 100%) the apparent plasma ANF concentrations measured with the other reference preparations varied from 42% to 178%.

Effects of insulin on renal haemodynamics and sodium handling in normal subjects

Diabetic patients treated with insulin injected subcutaneously are characterized by peripheral hyperinsulinaemia and an increased mass of total body exchangeable sodium. We hypothesized that this may cause, at least in part, the glomerular hyperfiltration seen in the diabetic state. Six normal subjects were studied on 2 days in random order. Day A: Basal state for 40 min, hyperinsulinaemic euglycaemic clamp for 1 h (insulin infusion rate 2 mU kg-1 min-1 and 50% glucose infusion) and hyperinsulinaemic euglycaemic clamp combined with volume expansion (2 1 isotonic sodium chloride) for 2 h. Day B: as day A, but without insulin and glucose infusion. During combined volume expansion and hyperinsulinaemia an increase in glomerular filtration rate (GFR) (128 +/- 6 vs 117 +/- 8 ml min-1 1.73 m-2, p less than 0.01) and lithium clearance (CLi) (50 +/- 4 vs 33 +/- 5 ml min-1 1.73 m-2, p less than 0.01) was observed compared with basal conditions. GFR and CLi were unchanged during day B. Insulin infusion reduced renal sodium excretion. Absolute proximal tubular reabsorption was unchanged on both days. Insulin infusion without volume expansion caused a decrease of 24% in the fractional distal sodium excretion. Superimposed volume expansion and the concomitant increase in GFR and CLi was accompanied by a subsequent enhanced fractional distal sodium excretion of 27%. The changes in plasma concentrations of aldosterone, renin, angiotensin II, atrial natriuretic peptide and catecholamines did not explain the differences in GFR. An increase in GFR of 10%, comparable with that observed in diabetic patients, was induced by combined hyperinsulinaemia and volume expansion in euglycaemic normal subjects. The enhanced GFR is probably a compensatory response to the sodium retention induced by the action of insulin on the distal tubules.

Effect of insulin on renal sodium handling in hyperinsulinaemic type 2 (non-insulin-dependent) diabetic patients with peripheral insulin resistance

The sodium retaining effect of insulin was studied in ten Type 2 (non-insulin-dependent) diabetic patients (mean age 56 (43-73) years, mean body mass index 29.5 (24.2-33.7) kg/m2) and eight age-matched control subjects (mean age 57 (43-68) years, mean body mass index 23.4 (20.8-26.6) kg/m2). The renal clearances of 99mTc-DTPA, lithium, sodium and potassium were measured over a basal period of 90 min. Then insulin was infused at a rate of 40 mU.min-1.m-2. After an equilibration period of 90 min, the clearance measurements were repeated during a new 90 min period. Blood glucose was clamped at the basal level (diabetic patients: 9.9 +/- 3.5, control subjects: 5.3 +/- 0.5 mmol/l) by a variable glucose infusion. Basal plasma insulin concentration was elevated in the diabetic patients (0.12 +/- 0.05 vs 0.05 +/- 0.02 pmol/ml, p less than 0.01). Insulin infusion resulted in comparable absolute increments in plasma insulin concentrations in the diabetic group and in the control group (0.44 +/- 0.13 vs 0.36 +/- 0.07 pmol/ml, NS). The metabolic clearance rate of glucose during the last 30 min of insulin infusion was lower in the diabetic patients (155 +/- 62 vs 320 +/- 69 ml.min-1.m-2, p less than 0.01), reflecting peripheral insulin resistance. The decline in sodium clearance during insulin infusion was similar in diabetic subjects (1.8 +/- 1.1 vs 0.7 +/- 0.4 ml.min-1.1.73 m-2, p less than 0.01) and in control subjects (1.7 +/- 0.3 vs 0.8 +/- 0.3 ml.min-1.1.73 m-2, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Unchanged extraction of atrial natriuretic factor across the chronic ischemic human kidney

The extractions of atrial natriuretic factor (EANF) and the glomerular filtration marker 51Cr-ethylenediamine tetraacetic acid (EEDTA) were determined before and after intravenous injection of furosemide across each of the two kidneys during renal vein catheterization in hypertensive patients with unilateral or bilateral renovascular disease. Before administration of furosemide, EANF was approximately 55% across both the more and the less affected kidney while EEDTA was significantly decreased across the more affected kidney. Significant lateralization of renin secretion to the more affected kidney was found, demonstrating an enhanced ipsilateral formation of renin. Administration of furosemide caused a significant decrease in EEDTA across the less affected kidney while the ipsilateral EANF did not change. Furosemide caused no change in EEDTA or EANF across the more affected kidney. No significant correlations were found between EANF and EEDTA. These results demonstrate that the extraction of ANF is unchanged across the chronic ischemic human kidney. Furthermore, in the single kidney, changes in EEDTA, as induced by furosemide, are not related to changes in ipsilateral EANF. Since the relation between simultaneously determined single kidney extractions of ANF and 51Cr-EDTA reflects the relation between the single kidney clearance of ANF and the ipsilateral glomerular filtration rate, our data indicate a dissociation between changes in the single kidney glomerular filtration rate and the ipsilateral total renal clearance of ANF.

Renal and endocrine effects of physiological variations of atrial natriuretic factor in normal humans

The renal and endocrine effects of incremental infusions of 3 and 6 ng.kg-1.min-1 of exogenous atrial natriuretic factor (ANF)-(99-126) or placebo were investigated in 10 normal subjects. A 90-min basal period was followed by two 2-h infusion periods with urine collection in the last 90 min of each period. Plasma ANF concentration increased by 50 and 150%, respectively, from a basal value of 6.2 +/- 3.1 pmol/l. Plasma guanosine 3',5'-cyclic monophosphate concentration increased in parallel with ANF. Blood pressure and heart rate were unchanged, whereas hematocrit was stepwise increased. 51Cr-EDTA clearance (GFR) did not change, but ANF caused an increase in Li clearance (a measure of end-proximal fluid delivery), Na clearance, and urine flow compared with time-matched control values. These excretory effects of ANF were mainly due to prevention of the 20- to 50% decreases occurring in the placebo series. Calculated values of fractional proximal and distal tubular Na reabsorption decreased significantly. ANF caused a decrease in plasma concentrations of active renin and aldosterone, whereas renin substrate, angiotensin I, and angiotensin II concentrations were unaltered. A subtle increase in plasma concentrations of norepinephrine and epinephrine was observed during the ANF infusions. These data suggest that the natriuretic effect of ANF is caused by an increased fluid delivery from the proximal tubule in addition to a fall in fractional distal Na reabsorption.

Enhanced fractional sodium reabsorption in the ischaemic kidney revisited with lithium as a probe

Extraction of lithium and 51Cr-EDTA across each of the two kidneys was determined during renal vein catheterization in 14 hypertensive patients with unilateral or bilateral renovascular disease before and after i.v. injection of furosemide. Before the administration of furosemide an increased fractional lithium reabsorption was demonstrated across the affected, or more affected kidney. This difference was abolished by furosemide. Using lithium as a probe for sodium, our data suggest an increased fractional tubular sodium reabsorption in the ischaemic human kidney probably located to the proximal tubules as well as to the loop of Henle. Determination of single-kidney fractional lithium reabsorption holds promise as a new research tool for future evaluation of functional abnormalities during divided renal function studies.

Normal renal tubular response to changes of sodium intake in hypertensive man

In a comparative study the influence of changes in dietary sodium intake on blood pressure, renal function, extracellular fluid volume, the renin-angiotensin-aldosterone system and plasma concentrations of arginine vasopressin, atrial natriuretic factor and cyclic guanosine monophosphate (GMP) was investigated in 12 patients with essential hypertension and in 10 normotensive controls. The subjects were studied after 4 days on a low (50 mmol/day), medium (180 mmol/day) or high (380 mmol/day) sodium intake. Renal sodium handling was assessed by simultaneous measurements of 51Cr-ethylenediaminetetraacetic acid (EDTA), lithium and sodium clearances. Identical values for the extracellular fluid volume, glomerular filtration rate and proximal and distal tubular resorption rates of sodium and water were found in the hypertensive patients and the controls at all three levels of sodium intake. In both groups, raising the sodium intake from low to high significantly increased 51Cr-EDTA and lithium clearance (an indirect measure of end-proximal fluid delivery), with intermediate values for the medium-sodium diet. The estimated values of fractional proximal and distal sodium resorption decreased when sodium intake was raised; the absolute proximal sodium resorption rate did not change, whereas the absolute distal sodium resorption rate as well as the extracellular fluid volume and sodium clearance increased. Blood pressure and the heart rate were unaffected by sodium intake. In both hypertensives and controls, plasma concentrations of active renin, angiotensin II and aldosterone decreased with increasing sodium intake, arginine vasopressin did not change, and atrial natriuretic factor and cyclic GMP increased.(ABSTRACT TRUNCATED AT 250 WORDS)

[Calcium antagonists: an antihypertensive alternative]

From a pathophysiological point of view, antihypertensive therapy with a vasodilator is rational. However, since traditional vasodilators, such as hydralazine, may cause retention of sodium and water, tachycardia and excessive stimulation of the renin-angiotensin-aldosterone system, they are not suitable for monotherapy. The Ca-antagonists include a number of drugs with quite different chemical structures. Ca-antagonists are powerful antihypertensive agents. This effect is due primarily to vasodilation caused by the interference with the excitation-contraction coupling in peripheral resistance vessels. All Ca-antagonists possess a natriuretic effect which apparently counteracts the sodium and water retention that vasodilation per se entails. Ca-antagonists cause no (verapamil) or a transient tachycardia (dihydropyridines) and they only cause a moderate and transient increase in plasma concentrations of renin and angiotensin II, whereas plasma aldosterone concentration is unaffected. Ca-antagonists have no metabolic side effects and in general the frequency of side effects is relatively low. Therefore, it is suggested that Ca-antagonists should be considered as possible first-choice agents along with diuretics, beta-blockers and angiotensin converting-enzyme inhibitors.

The acute effect of acetazolamide on glomerular filtration rate and proximal tubular reabsorption of sodium and water in normal man

The acute effects on kidney function of acetazolamide (250 mg) given intravenously were evaluated in seven healthy subjects. Glomerular filtration rate was measured as the renal clearance of 51Cr-EDTA, and fluid flow rate out of the proximal tubules was assessed by measurement of the renal lithium clearance. An 18% decline in glomerular filtration rate (ml/min) was observed after acetazolamide administration (109 +/- 16 vs 89 +/- 14, p less than 0.02), while lithium clearance (ml/min) increased by 35% (30 +/- 5 vs 38 +/- 8, p less than 0.02). Absolute proximal tubular reabsorption of water (ml/min) was reduced by about one third (79 +/- 12 vs 51 +/- 9, p less than 0.02), and fractional proximal reabsorption of water and sodium (%) declined (73 +/- 2 vs 58 +/- 6, p less than 0.02). Renal sodium clearance and absolute distal reabsorption of sodium increased, while fractional distal reabsorption of sodium declined. Acetazolamide reduces absolute and fractional proximal tubular reabsorption of sodium and water, and glomerular filtration rate. Primarily, this induces an increase in the output of fluid from the proximal tubules accounting for the diuretic effect of the drug. The acute fall in glomerular filtration rate is probably mediated by a temporary increase in proximal intratubular pressure and activation of the tubuloglomerular feedback mechanism.

Effects of insulin on kidney function and sodium excretion in healthy subjects

Insulin action on kidney function was evaluated in 8 healthy subjects, (mean age 27 years) using the euglycaemic clamp technique. Insulin was infused at rates of 0, 20 and 40 mU.min-1.m-2 over consecutive periods of 120 min resulting in plasma insulin concentrations of 8 +/- 2, 29 +/- 7 and 66 +/- 14 mU/l. The renal clearance of 51Cr-EDTA, lithium, sodium and potassium was determined during the last 90 min of each period. Sodium clearance declined with increasing plasma insulin concentrations (1.3 +/- 0.4, 1.0 +/- 0.3 and 0.5 +/- 0.2 ml.min-1.1.73 m-2, p less than 0.001), while glomerular filtration rate (108 +/- 21, 104 +/- 21 and 108 +/- 20 ml.min-1. 1.73 m-2) and lithium clearance (a marker of fluid flow rate from the proximal tubules) 29 +/- 5, 29 +/- 4 and 30 +/- 4 ml.min-1.1.73 m-2) remained unchanged. Calculated proximal tubular reabsorption of sodium and water was unchanged, while calculated distal fractional sodium reabsorption increased (95.5 +/- 1.5, 96.4 +/- 1.2 and 98.1 +/- 0.7%, p less than 0.001). Potassium clearance and plasma potassium concentration declined, whereas plasma aldosterone and plasma renin concentrations were unchanged. In conclusion, elevation of plasma insulin concentration within the physiological range has a marked antinatriuretic action. This effect is located distally to the proximal renal tubules.

The increased proximal tubular reabsorption of sodium and water is maintained in long-term insulin-dependent diabetics with early nephropathy

Proximal tubular reabsorption of sodium and water was investigated in long-term insulin-dependent diabetic patients with normoalbuminuria (group I, n = 19), microalbuminuria (group II, n = 39), diabetic nephropathy (group III, n = 12) and in 13 healthy age-matched subjects. Glomerular filtration rate was measured with the single injection, 51Cr-EDTA technique. The fluid flow rate out of the proximal tubules was assessed by the renal lithium clearance. Although glomerular filtration rate was significantly elevated in the diabetic patients (Group I: 122 +/- 16, Group II: 121 +/- 18, Group III: 110 +/- 17, CONTROLS: 105 +/- 13 ml/min X 1.73 m2), lithium clearance was similar in the four groups (Group I: 19 +/- 6, Group II: 22 +/- 7, Group III: 19 +/- 5, CONTROLS: 23 +/- 4 ml/min X 1.73 m2). Both absolute and fractional proximal reabsorption of sodium and water was enhanced in diabetes. Indices of distal tubular function did not differ between controls and patients with insulin-dependent diabetes. Sodium clearance was about the same in the four groups. Our study suggests that the enhanced proximal reabsorption of sodium and water in insulin-dependent diabetic patients is still observed despite the presence of incipient or overt diabetic nephropathy.

Interobserver agreement and accuracy of bedside estimation of right and left ventricular ejection fraction in acute myocardial infarction

Ninety-eight patients with acute myocardial infarction were examined by 3 clinicians who, independently of each other, gave an estimate of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) in each patient. Their estimates were based on physical examination, chest x-ray, electrocardiogram, patient history and clinical course during admission. Ejection fractions were estimated as belonging to 1 of 4 categories: normal (LVEF greater than or equal to 0.53, RVEF greater than or equal to 0.57), mildly reduced (LVEF 0.40 to 0.52, RVEF 0.45 to 0.56), moderately reduced (LVEF 0.30 to 0.39, RVEF 0.35 to 0.44) or severely reduced (LVEF less than 0.30, RVEF less than 0.35). Radionuclide ventriculography was carried out immediately after the physical examination. LVEF was correctly estimated in 43% of all examinations, deviated from radionuclide LVEF by 1 LVEF category in 45% and by 2 LVEF categories in 12%. The 3 clinicians agreed on estimated LVEF in only 32% of the patients. RVEF was correctly estimated in 67% of the examinations, but none of the clinicians identified greater than 43% of the relatively few patients with reduced radionuclide RVEF and they greatly disagreed as to who among the patients had a reduced RVEF. Previous myocardial infarction, electrocardiographic infarct location, Killip class, physical signs of left- and right-sided heart failure, radiographic pulmonary congestion and cardiomegaly were analyzed to determine which were the most helpful in predicting LVEF and RVEF. The results disclosed that several variables, traditionally believed to be reliable indexes of reduced ventricular function, were surprisingly poor predictors of LVEF and RVEF.

Unchanged lithium clearance during acute amiloride treatment in sodium-depleted man

To evaluate the validity of the lithium clearance method as a marker of overall proximal tubular fluid delivery in moderately sodium-depleted humans, the effects of a single dose of 10 mg amiloride on lithium clearance and glomerular filtration-rate were studied in normal volunteers maintained on a sodium diet of 50 mmol/day. Amiloride caused no changes of the glomerular filtration-rate or of lithium clearance. The effects of amiloride on tubular sodium, potassium and water handling were in accordance with a distal tubular action of amiloride. The results suggest that significant distal lithium reabsorption does not occur in measurable amounts during moderate sodium depletion in humans. The lithium clearance method may, therefore, be used to assess proximal fluid delivery in man when dietary sodium intake is as low as in the present study.

Changed cyclic guanosine monophosphate atrial natriuretic factor relationship in hypertensive man

Plasma concentrations of atrial natriuretic factor (ANF) and cyclic guanosine monophosphate (cGMP) were measured in 10 patients with essential hypertension and 10 normotensive controls on the fifth day of a low (50 mmol/day), a medium (180 mmol/day) and a high (380 mmol/day) dietary sodium intake. Plasma ANF and cGMP concentrations were less on the low than on the high sodium intake. Values for ANF on the medium sodium intake were intermediate. In normotensive subjects cGMP concentrations did not differ significantly on the low and the medium sodium intake. As compared with the controls plasma concentrations of cGMP were significantly increased in hypertensive patients on all three levels of sodium intake, while ANF concentrations were identical in the two groups. Since cGMP is a second messenger to ANF the data suggest an increased cellular response to ANF in patients with essential hypertension.

Lithium clearance and renal tubular sodium handling during acute and long-term nifedipine treatment in essential hypertension

1. In two separate studies the lithium clearance method was used to evaluate the influence of acute and long-term nifedipine treatment on renal tubular sodium reabsorption. 2. In the acute study, after a 4 week placebo period two doses of 20 mg of nifedipine decreased supine blood pressure from 155/101 (20.6/13.5) +/- 11/4 (1.5/0.5) to 139/88 (18.5/11.7) +/- 16/9 (2.1/1.2) mmHg (kPa) (means +/- SD; P less than 0.01). Lithium clearance, glomerular filtration rate and sodium clearance did not change. Therefore the calculated values of absolute proximal and absolute distal sodium reabsorption rates were also unchanged, as were potassium clearance, urine flow and body weight. 3. In the long-term study, lithium clearance, glomerular filtration rate, sodium clearance, potassium clearance, urine flow and body fluid volumes were measured after a 4 weeks placebo period and after 6 and 12 weeks of nifedipine treatment. As compared with placebo, mean supine blood pressure decreased significantly. The glomerular filtration rate did not change but lithium clearance fell by 30%. Consequently, the absolute and the fractional proximal sodium reabsorption increased significantly. The fractional distal sodium reabsorption did not change. Sodium clearance, fractional sodium excretion, potassium clearance, plasma volume and extracellular fluid volume were also unchanged. 4. In conclusion, we found no changes of renal tubular sodium reabsorption during acute nifedipine treatment, whereas long-term nifedipine treatment caused a redistribution of tubular sodium reabsorption without a change in overall sodium excretion or body fluid compartments.

Effects of acetazolamide on kidney function in type 1 (insulin-dependent) diabetic patients with diabetic nephropathy

We investigated the effects of 3 days treatment with acetazolamide 250 mg three times daily on kidney function in 8 Type 1 (insulin-dependent) diabetic patients with nephropathy, and in 7 healthy subjects in a double-blind placebo controlled cross-over study. Glomerular filtration rate and extracellular fluid volume were measured with the single injection 51Cr-EDTA technique and fluid flow rate from the proximal tubules was determined by measurement of the renal lithium clearance. A 24% decline in glomerular filtration rate was observed in both groups during acetazolamide treatment (control subjects: 108 +/- 11 vs 82 +/- 9 ml/min, p less than 0.02, diabetic patients: 71 +/- 19 vs 54 +/- 14 ml/min, p less than 0.01). The renal lithium clearance (ml/min) remained about the same (control subjects: 22 +/- 6 vs 27 +/- 8, NS, diabetic patients: 14 +/- 5 vs 15 +/- 4, NS). Absolute proximal tubular reabsorption of water (ml/min) was reduced by about one-third (control subjects: 85 +/- 11 vs 56 +/- 7, p less than 0.02, diabetic patients: 55 +/- 17 vs 37 +/- 6, p less than 0.02), and fractional proximal reabsorption of water and sodium (%) declined (control subjects: 79 +/- 5 vs 67 +/- 8, p less than 0.02, diabetic patients: 79 +/- 5 vs 72 +/- 6, p less than 0.02). Renal sodium clearance and distal fractional reabsorption of sodium was unchanged. Extracellular fluid volume declined by 10% in both groups (p less than 0.02). Albuminuria and fractional albumin clearance decreased significantly in the nephropathic patients (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)