Association Between Abnormal Myocardial Fatty Acid Metabolism and Cardiac-Derived Death Among Patients Undergoing Hemodialysis: Results From a Cohort Study in Japan

Association Between Disturbed Serum Phosphorus Levels and QT Interval Prolongation

Introduction

QT interval prolongation is a risk factor for fatal arrhythmias and other cardiovascular complications. QT interval prolongation in patients on hemodialysis (HD) is not well understood. Hypocalcemia is a suspected, but poorly verified etiology in these patients, and the association between serum phosphorus levels and QT interval prolongation is unknown. We sought to determine the prevalence of QT interval prolongation in patients on HD and to verify the association between predialysis serum calcium (Ca) and phosphate (P) levels and QT interval prolongation.

Methods

A cross-sectional study was conducted on adult patients on maintenance HD who were enrolled in the Japanese Society for Dialysis Therapy and Renal Data Registry 2019. After assessing patient characteristics, linear regression analysis was performed with predialysis serum Ca and P levels as exposures and a rate-corrected QT (QTc) interval as the outcome.

Results

A total of 204,530 patients were analyzed with a mean QTc of 451.2 (standard deviation, 36.9) ms. After multivariable analysis, estimated change in QTc (coefficients; 95% confidence interval) per 1 mg/dl increase in serum Ca and P was -2.02 (-3.00 to -1.04) and 5.50 (3.92-7.09), respectively. In the restricted cubic spline curve, estimated change in QTc increased with lower values of serum Ca. The correlation between serum P and QTc showed a U-shaped curve.

Conclusion

Decreased serum Ca levels and decreased and increased serum P levels may be associated with QT interval prolongation in patients on maintenance HD.

Pulmonary tumor embolism in a maintenance hemodialysis patient with hepatocellular carcinoma

Patients with chronic kidney disease are already at an increased risk for pulmonary embolism, since loss of renal function rendered a procoagulant state. Further, malignant tumor is a well-established risk factor for pulmonary thromboembolism. Alternatively, occlusion of the pulmonary vasculature by tumor cells per se and associated thrombi may mimic thromboembolic disease. By comparison, however, report of pulmonary tumor embolism (PTE) in patients on maintenance hemodialysis (MHD) is exceedingly rare. A less vigilant clinician may have otherwise treated this situation as fluid overload or thromboembolic disorder. We herein described in an MHD patient such an unusual case of PTE, which was diagnosed by contrast-enhanced CT and PET/CT. As such, our work may expand the knowledge reserve of dialysis staffs about this rare complication of malignancy.

Practice recommendation for measuring washout rates in 123I-BMIPP fatty acid images

The purpose of this practice recommendation is to specifically identify the critical steps involved in performing and interpreting 123I-β-methyl-iodophenyl-pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) and measurement of washout rate (WR) from the heart. This document will cover backgrounds, patient preparation, testing procedure, visual image interpretation, quantitation methods using planar and SPECT studies, and reporting of WR. The pitfall and some tips for the calculation of 123I-BMIPP WR are also included. The targets of global and regional WR calculation include ischemic heart disease, cardiomyopathy, heart failure, and triglyceride deposit cardiomyovasculopathy, an emerging rare heart disease.

Practice Recommendation for Measuring Washout Rates in 123I-BMIPP Fatty Acid Images

The purpose of this practice recommendation is to specifically identify the critical steps involved in performing and interpreting 123I-β-methyl-iodophenyl-pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) and measurement of washout rate (WR) from the heart. This document will cover backgrounds, patient preparation, testing procedure, visual image interpretation, quantitation methods using planar and SPECT studies, and reporting of WR. The pitfall and some tips for the calculation of 123I-BMIPP WR are also included. The targets of global and regional WR calculation include ischemic heart disease, cardiomyopathy, heart failure, and triglyceride deposit cardiomyovasculopathy, an emerging rare heart disease.

Association of Hyperkalemia and Hypokalemia with Patient Characteristics and Clinical Outcomes in Japanese Hemodialysis (HD) Patients

This study aimed to examine the characteristics and clinical outcomes of Japanese hemodialysis patients with dyskalemia. A retrospective study was conducted using a large Japanese hospital group database. Outpatients undergoing thrice-a-week maintenance hemodialysis were stratified into hyperkalemia, hypokalemia, and normokalemia groups based on their pre-dialysis serum potassium (sK) levels during the three-month baseline period. Baseline characteristics of the three groups were described and compared for the following outcomes during follow-up: all-cause mortality, all-cause hospitalization, major adverse cardiovascular events (MACE), cardiac arrest, fatal arrythmia, and death related to arrhythmia. The study included 2846 eligible patients, of which 67% were men with a mean age of 65.65 (SD: 12.63) years. When compared with the normokalemia group (n = 1624, 57.06%), patients in the hypokalemia group (n = 313, 11.00%) were older and suffered from malnutrition, whereas patients in the hyperkalemia group (n = 909, 31.94%) had longer dialysis vintage. The hazard ratios for all-cause mortality and MACE in the hypokalemia group were 1.47 (95% confidence interval [CI], 1.13–1.92) and 1.48 (95% CI, 1.17–1.86), respectively, whereas that of death related to arrhythmia in the hyperkalemia group was 3.11 (95% CI, 1.03–9.33). Thus, dyskalemia in maintenance hemodialysis patients was associated with adverse outcomes, suggesting the importance of optimized sK levels.

Near-sudden unexpected death in a patient with epilepsy undergoing hemodialysis: a case report

Sudden unexpected death in epilepsy (SUDEP) has been defined as a sudden/unexpected, witnessed/unwitnessed, nontraumatic, and nondrowning death in epileptic patients with/without seizure evidence and documented status epilepticus. Identified as the leading cause of epilepsy-related deaths, SUDEP cases are highly unrecognized and underreported due to diagnostic difficulty. We report a case of a successfully revived hemodialysis patient who developed cardiopulmonary arrest after a witnessed convulsive seizure. Electroencephalogram revealed epileptic abnormalities. Therefore, this case could be seizure-induced cardiopulmonary arrest and near-SUDEP. Hence, the possibility of SUDEP should be considered even in hemodialysis patients having conventional coronary risk factors for sudden cardiac death.

Optimal blood pressure for the minimum all-cause mortality in Chinese ESRD patients on maintenance hemodialysis

Blood pressure (BP) is a known prognostic marker for mortality in patients on maintenance hemodialysis (MHD). However, definition of the BP and its optimal values vary essentially among different MHD populations. Our purpose was to clarify these important clinical parameters in a Chinese MHD cohort. Accordingly, we reviewed the available records of patients on regular MHD during the past 10 years and made a comparison between the deceased (n=81) and survival ones (n=131). Multiple logistic regression and Kaplan–Meier survival analysis were used to examine the effect of BP on mortality and long-term survival, respectively. The all-cause mortality in our patients was 38.2%, in which 49.4% was from cardio-cerebrovascular deaths. Using the multiple logistic regression, we found that the sitting (the same definition hereafter) pre-dialysis systolic BP (SBP) was significantly associated with both the all-cause mortality and cardio-cerebrovascular deaths exclusively in patients of 60–80 years. Moreover, a pre-dialysis SBP of 140–160 mmHg in these patients had the minimum all-cause mortality (23.5%) against that conferred by either a lower (42.1%) or higher SBP value (61.5%). This observation was further confirmed by the Kaplan–Meier survival analysis. As fresh gain to the practice of hemodialysis, our report revealed that BP worked in a time-dependent way among a Chinese MHD cohort and highlighted a U-shaped association between the pre-dialysis SBP and all-cause mortality. These findings may hence help to obtain optimal BP control for better survival and lend some prognostic insight into mortality in these MHD patients.

The Incidence and Associated Factors of Sudden Death in Patients on Hemodialysis: 10-Year Outcome of the Q-Cohort Study

Aim: The incidence of sudden death and its risk factors in patients on hemodialysis remain unclear. This study aimed to clarify the incidence of sudden death and its risk factors in Japanese patients on hemodialysis.

Methods: A total of 3505 patients on hemodialysis aged ≥ 18 years were followed for 10 years. Multivariate-adjusted hazard ratio (HR) with 95% confidence interval (95% CI) of each risk factor of sudden death were calculated using a Cox proportional hazards model.

Results: During the 10-year follow-up, 1735 patients died, including 227 (13%) sudden deaths. The incidence rate of sudden death was 9.13 per 1000 person-years. In multivariable-adjusted Cox analysis, male sex (HR 1.67; 95% CI 1.20–2.33), age (HR 1.44; 95% CI 1.26–1.65 per 10-year higher), the presence of diabetes (HR 2.45; 95% CI 1.82–3.29), history of cardiovascular disease (HR 1.85; 95% CI 1.38–2.46), cardiothoracic ratio (HR 1.21; 95% CI 1.07–1.39 per 5% higher), serum C-reactive protein (HR 1.11; 95% CI 1.03–1.20 per 1-mg/dL higher), and serum phosphate (HR 1.15; 95% CI 1.03–1.30 per 1-mg/dL higher) were independent predictors of sudden death. A subgroup analysis stratified by sex or age showed that lower serum corrected calcium levels, not using vitamin D receptor activators in women, and a shorter dialysis session length in men or older people (≥ 65 years) increased the risk for sudden death.

Conclusions: This study clarified the incidence of sudden death and its specific predictors in Japanese patients on hemodialysis.

The Cardiorenal Axis: Myocardial Perfusion, Metabolism, and Innervation

PURPOSE OF THE REVIEW

Cardiorenal syndrome (CRS), defined as concomitant heart and kidney disease, has been a focus of attention for nearly a decade. As more patients survive severe acute and chronic heart and kidney diseases, CRS has emerged as an "epidemic" of modern medicine. Significant advances have been made in unraveling the complex mechanisms that underlie CRS based on classification of the condition into five pathophysiologic subtypes. In types 1 and 2, acute or chronic heart disease results in renal dysfunction, while in types 3 and 4, acute or chronic kidney diseases are the inciting factors for heart disease. Type 5 CRS is defined as concomitant heart and kidney dysfunction as part of a systemic condition such as sepsis or autoimmune disease.

RECENT FINDINGS

There are ongoing efforts to better define subtypes of CRS based on historical information, clinical manifestations, laboratory data (including biomarkers), and imaging characteristics. Systematic evaluation of CRS by advanced cardiac imaging, however, has been limited in scope and mostly focused on type 4 CRS. This is in part related to lack of clinical trials applying advanced cardiac imaging in the acute setting and exclusion of patients with significant renal disease from studies of such techniques in chronic HF. Advanced cardiac nuclear imaging is well poised for assessment of the pathophysiology of CRS by offering a myriad of molecular probes without the need for nephrotoxic contrast agents. In this review, we examine the current or potential future application of advanced cardiac imaging to evaluation of myocardial perfusion, metabolism, and innervation in patients with CRS.

L-carnitine Improved the Cardiac Function via the Effect on Myocardial Fatty Acid Metabolism in a Hemodialysis Patient

Patients on hemodialysis often have carnitine deficiency. We herein report a woman who experienced the dramatic improvement of cardiac dysfunction after intravenous L-carnitine administration. We also investigated the myocardial fatty acid metabolism using ¹²³I-labeled β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT) before and after L-carnitine therapy, and the impaired metabolism was ameliorated. Taken together, these findings indicate that L-carnitine therapy improved cardiac dysfunction via the amelioration of the abnormal myocardial fatty acid metabolism, at least in part.

Effects of L- and N-Type Ca Channel Blocker Cilnidipine on Changes in Heart Rate and QT Interval During Dialysis

BACKGROUND/AIMS

Hemodialysis patients have poor prognosis due to increased prevalence of cardiovascular diseases. Treatment to suppress increases in sympathetic nerve activity and QT prolongation may have the potential to reduce the occurrence of these events. The L/N-type Calcium (Ca) channel blocker cilnidipine has unique inhibitory action to inhibit sympathetic nerve activity and in a canine model ameliorates QT prolongation. In this study, we investigated whether cilnidipine has inhibitory effects on heart rate, an index of sympathetic nerve activity, and QT prolongation in patients undergoing dialysis.

METHODS

An L-type Ca channel blocker amlodipine was administered for 4 weeks followed by cilnidipine treatment for 4 weeks. On the last day of each period, heart rate and corrected QT interval were estimated and compared between the two periods.

RESULTS

Cilnidipine showed greater suppression of heart rate during dialysis than did amlodipine. The corrected QT interval in one dialysis session was significantly increased, and 3 of 17 patients showed prominent QT prolongation during administration of amlodipine but not cilnidipine.

CONCLUSION

These data suggested that cilnidipine may inhibit increases in heart rate and QT interval. Cilnidipine may have beneficial effects in reducing cardiovascular events, resulting from increased sympathetic nerve activity and lethal arrhythmias in hemodialysis patients.

Obesity and the risk of cardiovascular and all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

Background

Obesity is a risk factor for cardiovascular disease and death in people without chronic kidney disease (CKD), but the effect of obesity in people with CKD is uncertain.

Methods

Medline and Embase (from inception to January 2015) were searched for cohort studies measuring obesity by body mass index (BMI), waist:hip ratio (WHR) and/or waist circumference (WC) and all-cause and cardiovascular mortality or events in patients with any stage of CKD. Data were summarized using random effects models. Meta-regression was conducted to assess sources of heterogeneity.

Results

Of 4065 potentially eligible citations, 165 studies ( n = 1 534 845 participants) were analyzed. In studies that found a nonlinear relationship, underweight people with CKD (3-5) on hemodialysis experienced an increased risk of death compared with those with normal weight. In transplant recipients, excess risk was observed at levels of morbid obesity (>35 kg/m 2 ). Of studies that found the relationship to be linear, a 1 kg/m 2 increase in BMI was associated with a 3 and 4% reduction in all-cause and cardiovascular mortality in patients on hemodialysis, respectively {adjusted hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.96-0.98] and adjusted HR 0.96 (95% CI 0.92-1.00)}. In CKD Stages 3-5, for every 1 kg/m 2 increase in BMI there was a 1% reduction in all-cause mortality [HR 0.99 (95% CI 0.0.97-1.00)]. There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis. Sparse data for WHR and WC did not allow further analyses.

Conclusions

Being obese may be protective for all-cause mortality in the predialysis and hemodialysis populations, while being underweight suggests increased risk, but not in transplant recipients.

Mineral metabolism and cardiovascular disease in CKD

The mineral bone disorder of CKD, called Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD), has a major role in the etiology and progression of cardiovascular disease in CKD patients. Since the main emphasis in CKD-MBD is on three categories (bone abnormalities, laboratory abnormalities, and vascular calcifications), we have routinely accepted ectopic cardiovascular calcifications as a central risk factor in the pathophysiology of CKD-MBD for cardiac events. However, recent compelling evidence suggests that some CKD-MBD-specific factors other than vascular calcification might contribute to the onset of cardiovascular disease. Most notable is fibroblast growth factor-23 (FGF23), which is thought to be independently associated with cardiac remodeling. Slow progression of cardiac disorders, such as vascular calcification and cardiac remodeling, characterizes cardiac disease due to CKD-MBD. In contrast, fatal arrhythmia may be induced when QT prolongation occurs with CKD-MBD treatment, such as with lower Ca dialysate or the use of calcimimetics. Sudden onset of fatal cardiac events, such as heart failure and sudden cardiac death, due to fatal arrhythmia would be another distinctive phenomenon of CKD-MBD. This may be defined as CKD-MBD-specific cardiac complex syndrome.

Anaemia and early phase cardiovascular events on haemodialysis

Although the mechanism of the cardio-renal anaemia syndrome (CRAS) has been elucidated in considerable detail over the past decade, cardiovascular disease (CVD) remains a leading cause of death among patients with end-stage kidney disease (ESKD) undergoing haemodialysis, and these patients' cardiovascular mortality is greater than that of the general population. Recent studies have reported that the CVD risk increases with advancing chronic kidney disease (CKD) stage. Furthermore, the incidence of cardiovascular events is highest during the first week after dialysis initiation, with increased risk in incident haemodialysis patients. This accumulated evidence demonstrates that how patients are managed during the pre-dialysis phase may have important implications on long-term outcomes in ESKD. Anaemia, a non-traditional risk factor for CVD, advances exponentially along with declining kidney function due to insufficient erythropoietin production. Anaemia causes functional abnormalities of the heart, as represented by cardiac hypertrophy, which results from increased cardiac workload induced by an increased preload. Left ventricular hypertrophy (LVH), a traditional risk factor for CVD, is especially associated with advanced CKD stage and could be a major risk factor for cardiovascular complications such as ischaemic heart disease, heart failure, and sudden cardiac death. In ESKD, anaemia develops more severely and requires a higher amount of erythropoiesis-stimulating agent (ESA) therapy before dialysis initiation. This suggests that improvement in anaemia management during the pre-dialysis phase may have a beneficial effect on cardiac hypertrophy and contribute to reducing the CVD risk after initiating haemodialysis.

Incidence of sudden cardiac death in adults with end-stage renal disease: a systematic review and meta-analysis

BACKGROUND

Although sudden cardiac death (SCD) is recognized as a distinct cause of death in patients with end stage renal disease (ESRD), its incidence has not been well summarized.

METHODS

We performed a systematic review and meta-analysis of the literature based on a protocol developed a priori. We searched MEDLINE and EMBASE (inception to March 2015) for randomized controlled trials and cohort studies reporting the incidence of SCD in adult patients with ESRD on hemodialysis or peritoneal dialysis. We collected data on number of SCD as well as the definition of SCD for each individual study. A random-effects model was used to summarize the incidence of SCD. We conducted subgroup analyses to explore sources of heterogeneity.

RESULTS

Forty two studies (n = 80,382 patients) were included in the meta-analysis. The incidence of SCD among adults with ESRD ranged from 0.4 to 10.04 deaths per 100 person-years. The definitions and assessment of SCD varied across the included studies. There was evidence of significant heterogeneity (I(2) = 98; p < 0.001), which was not explained by subgroup analyses stratified by mean age, proportion of hypertensive or diabetic patients, follow-up time, study size, or type of cohort studied.

CONCLUSION

Current estimates of the incidence of SCD among adults with ESRD vary widely. There is a need for further studies to more accurately estimate the incidence of SCD in patients with ESRD.

The FRAX ® as a predictor of mortality in Japanese incident hemodialysis patients: an observational, follow-up study

The World Health Organization Fracture Risk Assessment Tool (FRAX(®)) was recently developed to estimate the 10-year absolute risk of osteoporotic fracture among the general population. However, the evidence for its use in chronic kidney disease patients has been lacking, and the association between the FRAX(®) and mortality is unknown. Therefore, a hospital-based, prospective, cohort study was conducted to evaluate the predictive ability of the FRAX(®) for mortality in hemodialysis patients. A total of 252 patients who had been started on maintenance hemodialysis, 171 men and 81 women, with a mean age of 67 ± 14 years, was studied. The endpoint was defined as all-cause death. The Cox proportional hazards model was used to calculate hazard ratios and 95 % confidence intervals. During the mean follow-up period of 3.4 ± 2.7 years, 61 deaths occurred. The median (interquartile range) of the FRAX(®) for major osteoporotic fracture was 6.9 (4.6-12.0) % in men and 19.0 (7.6-33.0) % in women. Cumulative survival rates at 5 years after starting dialysis, with the FRAX(®) levels above and below the median, were 51.9 and 87.9 %, respectively, in men and 67.4 and 83.7 %, respectively, in women. Overall, in men, the multivariate Cox regression analyses revealed that the log-transformed FRAX(®) remained an independent predictor of death after adjusting by confounding variables. However, in women, the significant association between the FRAX(®) value and the outcome was eliminated if age was put into these models. Among Japanese hemodialysis patients, the FRAX(®) seems to be useful for predicting death, especially in men.

Cardiac event risk stratification in patients with end-stage renal disease: Sub-analysis of the B-SAFE study

BACKGROUND

The aim of this study was to investigate whether 123I-labelled β-methyl iodophenyl-pentadecanoic acid (BMIPP) imaging as an abnormal myocardial fatty acid metabolism indicator better predicted fatal and non-fatal cardiac events than conventional predictors [e.g. peripheral artery disease (PAD) and diabetes mellitus (DM)] in haemodialysis patients.

METHODS

In a sub-analysis of the BMIPP SPECT Analysis for Decreasing Cardiac Events in Haemodialysis Patients (B-SAFE) study, 677 asymptomatic patients with ≥1 cardiovascular risk factor and without known coronary artery disease were followed for 3 years. The amount of radioactivity in each 17-left ventricular segment was graded visually and assigned a score from 0 (normal) to 4 (absent). Its total values were designated as baseline summed BMIPP scores. Outcome measures were composite cardiac events.

RESULTS

Cardiac events correlated with age, PAD [hazard ratio (HR): 2.15; p=0.003], DM (HR: 1.76; p=0.006) and summed BMIPP scores (4-8, HR: 1.82; p<0.001; ≥9, HR: 3.49; p<0.001). Cardiac event-free rates decreased with increasing summed BMIPP scores, PAD and DM. Areas under the receiver operating curves (AUCs) indicated that a BMIPP-based model (AUC: 0.656) was more predictive than DM or PAD models (AUC: 0.591); a model with all three was most predictive (AUC: 0.708). The three-year cardiac event-free rates significantly decreased in patients with PAD and/or DM in all summed BMIPP score categories.

CONCLUSIONS

Abnormal myocardial fatty acid metabolism strongly predicts cardiac events in haemodialysis patients; those with PAD or DM are at high risk for cardiac events.

Current status of nuclear cardiology in Japan: Ongoing efforts to improve clinical standards and to establish evidence

Nuclear cardiology imaging tests are widely performed in Japan as clinical practice. The Japanese nuclear cardiology community has developed new diagnostic imaging tests using (123)I-beta-methyl-p-iodophenyl-pentadecanoic acid, (123)I-metaiodobenzylguanidine, and (18)F-fluorodeoxyglucose PET for detecting cardiac involvement in sarcoidosis. These tests have become popular worldwide. The Japanese Circulation Society and the Japanese Society of Nuclear Cardiology have published clinical imaging guidelines showing indications and standards for the new imaging tests. JSNC is currently striving to improve the standard of clinical practice and is promoting research activities.

Usefulness of an Upright T-Wave in Lead aVR for Predicting the Short-Term Prognosis of Incident Hemodialysis Patients: A Potential Tool for Screening High-Risk Hemodialysis Patients

BACKGROUND/AIMS

An upright T-wave in lead aVR (aVRT) has recently been reported to be associated with cardiovascular death and mortality among the general population and patients with prior cardiovascular disease (CVD). However, evidence for the predictive ability of aVRT in patients with chronic kidney disease is lacking. Therefore, a hospital-based, prospective, cohort study was conducted to evaluate the predictive ability of an upright aVRT for the short-term prognosis in incident hemodialysis patients.

METHODS

Among 208 patients who started maintenance hemodialysis, 79 with preexisting CVD (CVD cohort) and 129 with no history of CVD (non-CVD cohort), were studied. An upright and non-upright aVRT were defined as a wave with a positive deflection in amplitude of ≥0 mV and a negative deflection in amplitude of <0 mV, respectively. The endpoint was all-cause death.

RESULTS

Overall, the prevalence of an upright aVRT was 22.6% at baseline. During the mean follow-up period of 2.1 ± 1.0 years, 33 deaths occurred. Cumulative survival rates at 3 years after starting dialysis in patients with an upright and non-upright aVRT were 50.0 and 80.7%, respectively, in the CVD cohort and 92.0 and 91.3%, respectively, in the non-CVD cohort. In the CVD cohort, multivariate Cox regression analysis showed that an upright aVRT was an independent predictor of death after adjusting for confounding variables.

CONCLUSION

Among Japanese hemodialysis patients at high risk for CVD, an upright aVRT seems to be useful for predicting death.

Effects of intravenous l-carnitine on myocardial fatty acid imaging in hemodialysis patients: responders or non-responders to l-carnitine

We investigated whether chronic intravenous administration of l-carnitine could improve myocardial fatty acid imaging in patients on maintenance hemodialysis. We enrolled 72 hemodialysis patients who had impaired myocardial fatty acid imaging and left ventricular dysfunction not based on coronary lesion. l-Carnitine (1,000 mg) was intravenously administered after dialysis for 1 year to 36 participants (Carnitine group), while not in the other 36 participants (Control group). Single-photon emission computed tomography (SPECT) using an iodinated fatty acid analogue, BMIPP, was performed. Uptake on SPECT images was graded in 17 segments on a five-point scale (0, normal; 4, absent) and assessed as BMIPP summed scores. During follow-up, 19 participants were discontinued from the study, and 53 participants (65 ± 12 years: 27 carnitine, 26 control) were analyzed. The mean BMIPP summed scores 1 year after carnitine administration did not differ from that before in the carnitine group, nor from that in the control group. However, improved SPECT (Changes in BMIPP summed scores <−20%) was found in 7 (25.9%) participants in the carnitine, whereas in 2 (7.7%) in the control group. Multivariate logistic analysis showed the improved SPECT was inversely associated with baseline serum albumin levels (1 g/L: odds ratio, 0.669); the cut-off was 35 g/L. Chronic intravenous l-carnitine might improve myocardial fatty acid imaging in a selected group of hemodialysis patients with hypoalbuminemia.

Focal impairment in myocardial fatty acid imaging in the left anterior descending artery area, a strong predictor for cardiac death in hemodialysis patients without obstructive coronary artery disease

Purpose

We investigated whether impaired patterns of myocardial fatty acid imaging were associated with cardiac death in dialysis patients without coronary lesions.

Methods

We prospectively enrolled 155 hemodialysis patients without obstructive coronary artery disease, who had been examined by single-photon emission computed tomography (SPECT) using the iodinated fatty acid analogue BMIPP. Uptake of BMIPP on SPECT was graded in 17 segments on a five-point scale (0, normal; 4, absent) and assessed as BMIPP summed scores. Of the enrolled 155 participants, we analyzed 95 who had BMIPP summed scores ≥ 6 (52 men and 43 women, 65 ± 11 years). BMIPP scores ≥ 2 in ≥ 2 consecutive segments in SPECT were defined as focal, and the others as non-focal pattern.

Results

Of 95 participants analyzed, 42 (44.2 %) showed focal and 53 (55.8 %) non-focal type. During follow-up for 5.1 ± 2.0 years, 42 died of cardiac events. The occurrence of cardiac death was higher in the focal than in the non-focal group (30/42 [71.4 %] versus 12/53 [22.6 %], p = 0.001). In stepwise Cox hazard analysis, focal pattern was associated with cardiac death (hazard ratio 2.266), independent of impairment of BMIPP SPECT (BMIPP summed scores ≥ 12). The predictive potential of BMIPP SPECT for cardiac death was higher (p < 0.001) in the left anterior descending artery area compared with other coronary territories.

Conclusions

Focal impairment in myocardial fatty acid imaging in the left anterior descending area may strongly predict cardiac death in this population.

Improvement of myocardial fatty acid metabolism by oral nicorandil in hemodialysis patients without coronary artery disease

BACKGROUND

We investigated the potential of oral nicorandil to improve myocardial fatty acid metabolism assessed by single-photon emission computed tomography (SPECT) using (123)I-β-methyliodophenyl pentadecanoic acid (BMIPP) in hemodialysis patients without obstructive coronary artery disease (CAD).

METHODS

This study was based on a cohort study of 155 hemodialysis patients with angiographic absence of obstructive CAD, with analysis performed in 100 propensity-matched patients (54 men and 46 women, 64 ± 10 years); 50 with oral administration of nicorandil (15 mg/d, nicorandil group) and 50 without (control). BMIPP SPECT was performed every year after angiography. Uptake on SPECT was graded in 17 segments on a five-point scale (0 normal, 4 absent) and assessed as BMIPP summed scores (SS).

RESULTS

Over a mean follow-up period of 5.3 ± 1.9 years, we observed 25 cardiac deaths among 100 propensity-matched patients. Myocardial uptake of BMIPP in SPECT improved in the nicorandil group compared with the control group from 2 years of administration. In Kaplan-Meier survival analyses, free survival rate from cardiac death was higher in patients with a BMIPP SS improvement rate of ≥20% compared to those with ≥0% <20% or with <0% BMIPP SS improvement rate. At multiple logistic analysis, a ≥20% BMIPP SS improvement rate was positively associated with serum albumin concentration and oral nicorandil.

CONCLUSIONS

Long-term oral nicorandil may inhibit cardiac death by improving myocardial fatty acid metabolism in hemodialysis patients without obstructive CAD.

Myocardial perfusion imaging for predicting cardiac events in Japanese patients with advanced chronic kidney disease: 1-year interim report of the J-ACCESS 3 investigation

PURPOSE

Whether myocardial perfusion imaging (MPI) can predict cardiac events in patients with advanced conservative chronic kidney disease (CKD) remains unclear.

METHODS

The present multicenter prospective cohort study aimed to clarify the ability of MPI to predict cardiac events in 529 patients with CKD and estimated glomerular filtration rates (eGFR) < 50 ml/min per 1.73(2) without a definitive diagnosis of coronary artery disease. All patients were assessed by stress-rest MPI with (99m)Tc-tetrofosmin and analyzed using summed defect scores and QGS software. Cardiac events were analyzed 1 year after registration.

RESULTS

Myocardial perfusion abnormalities defined as summed stress score (SSS) ≥4 and ≥8 were identified in 19 and 7 % of patients, respectively. At the end of the 1-year follow-up, 33 (6.2 %) cardiac events had occurred that included cardiac death, sudden death, nonfatal myocardial infarction, and hospitalization due to heart failure. The event-free rates at that time were 0.95, 0.90, and 0.81 for groups with SSS 0-3, 4-7, and ≥8, respectively (p = 0.0009). Thus, patients with abnormal SSS had a higher incidence of cardiac events. Multivariate Cox regression analysis showed that SSS significantly impacts the prediction of cardiac events independently of eGFR and left ventricular ejection fraction.

CONCLUSION

MPI would be useful to stratify patients with advanced conservative CKD who are at high risk of cardiac events without adversely affecting damaged kidneys.

Diagnostic utility of 123I-BMIPP imaging in patients with Takotsubo cardiomyopathy

OBJECTIVE

Takotsubo cardiomyopathy is a cardiac syndrome with an acute onset defined by chest symptoms and ST segment elevation on electrocardiograms. Takotsubo cardiomyopathy is sometimes misdiagnosed as acute myocardial infarction (AMI). Therefore a non-invasive diagnostic method is needed to be established for setting up appropriate strategies. The purpose of this study was to detect myocardial metabolic abnormalities and to determine the diagnostic usefulness of (123)I-beta-methy-iodophenyl pentadecanoic acid ((123)I-BMIPP) imaging in patients with takotsubo cardiomyopathy.

METHODS AND RESULTS

We examined 16 patients with takotsubo cardiomyopathy and 12 with AMI in the left anterior descending artery. All patients were studied with resting (123)I-BMIPP imaging. Total defect score (TDS) of (123)I-BMIPP and perfusion were semi-quantitatively determined with single-photon emission computed tomography (SPECT) imaging using a 17-segment 5-point model. TDS of (123)I-BMIPP were 4.8 ± 2.7 in patients with Takotsubo cardiomyopathy and 22.4 ± 10.7 in AMI. The ratio of summed BMIPP defect score of non-apical to apical segments in Takotsubo cardiomyopathy was smaller than that of the patients with AMI (0.1 ± 0.1 vs. 1.1 ± 0.7, p < 0.0001), indicating that (123)I-BMIPP abnormalities were exclusively observed the in apical area. The ratio of summed perfusion defect scores of non-apical to apical segments in takotsubo cardiomyopathy did not differ significantly from that of AMI (0.52 ± 0.6 vs. 0.57 ± 0.3, p = NS). Summed BMIPP defect score in the apical area of takotsubo cardiomyopathy was larger than that of perfusion defect score (3.9 ± 2.7 vs. 1.8 ± 1.8, p = 0.04).

CONCLUSION

Impaired metabolic metabolism exclusively in the apical region was observed by (123)I-BMIPP SPECT images in takotsubo cardiomyopathy. These typical metabolic SPECT features of the disease can be utilized on differential diagnosis of takotsubo cardiomyopathy.

Recent advances in metabolic imaging

Abnormalities in myocardial substrate metabolism play a central role in the manifestations of most forms of cardiac disease such as ischemic heart disease, heart failure, hypertensive heart disease, and the cardiomyopathy due to either obesity or diabetes mellitus. Their importance is exemplified by both the development of numerous imaging tools designed to detect the specific metabolic perturbations or signatures related to these different diseases, and the vigorous efforts in drug discovery/development targeting various aspects of myocardial metabolism. Since the prior review in 2005, we have gained new insights into how perturbations in myocardial metabolism contribute to various forms of cardiac disease. For example, the application of advanced molecular biologic techniques and the development of elegant genetic models have highlighted the pleiotropic actions of cellular metabolism on energy transfer, signal transduction, cardiac growth, gene expression, and viability. In parallel, there have been significant advances in instrumentation, radiopharmaceutical design, and small animal imaging, which now permit a near completion of the translational pathway linking in-vitro measurements of metabolism with the human condition. In this review, most of the key advances in metabolic imaging will be described, their contribution to cardiovascular research highlighted, and potential new clinical applications proposed.

Ischaemic memory imaging using metabolic radiopharmaceuticals: overview of clinical settings and ongoing investigations

"Ischaemic memory" is defined as a prolonged functional and/or biochemical alteration remaining after a particular episode of severe myocardial ischaemia. The biochemical alteration has been reported as metabolic stunning. Metabolic imaging has been used to detect the footprint left by previous ischaemic episodes evident due to delayed recovery of myocardial metabolism (persistent dominant glucose utilization with suppression of fatty acid oxidation). β-Methyl-p-[(123)I]iodophenylpentadecanoic acid (BMIPP) is a single-photon emission computed tomography (SPECT) radiotracer widely used for metabolic imaging in clinical settings in Japan. In patients with suspected coronary artery disease but no previous myocardial infarction, BMIPP has shown acceptable diagnostic accuracy. In particular, BMIPP plays an important role in the identification of prior ischaemic insult in patients arriving at emergency departments with acute chest pain syndrome. Recent data also show the usefulness of (123)I-BMIPP SPECT for predicting cardiovascular events in patients undergoing haemodialysis. Similarly, SPECT or PET imaging with (18)F-FDG injected during peak exercise or after exercise under fasting conditions shows an increase in FDG uptake in postischaemic areas. This article will overview the roles of ischaemic memory imaging both under established indications and in ongoing investigations.