Serum creatinine is an unreliable marker of renal function in patients undergoing heart transplantation

BACKGROUND

Renal dysfunction is a common complication after heart transplantation (Htx). Glomerular filtration rate (GFR) can be assessed by various estimating equations (eGFR). We evaluated the correlation, agreement, and accuracy between eGFR and mGFR and the ability of eGFR to track changes in mGFR early after Htx.

METHODS

A single-center prospective observational study on 55 patients undergoing Htx. Serum creatinine and mGFR (plasma clearance of Cr51-EDTA or iohexol) were measured preoperatively and on the fourth postoperative day. The accuracy of eGFR to predict true mGFR was calculated as the percentage of patients with an eGFR within 30% of mGFR (P30). The agreement between eGFR and mGFR was assessed according to Bland and Altman. A four-quadrant plot was made to evaluate the ability of eGFR to track changes in mGFR.

RESULTS

The accuracy of eGFR to assess mGFR was 52%. The bias was 11.2 ± 17.4 mL/min/1.72 m2. The limits of agreement were -23.0 to 45.4 mL/min/1.72 m2 and the error 58%. The concordance rate between eGFR and mGFR was 72%.

CONCLUSIONS

eGFR underestimated mGFR and the agreement between eGFR and mGFR was low with an unacceptably large between-group error and low accuracy. Furthermore, the ability of eGFR to assess changes in mGFR, postoperatively, was poor. Thus, the use of estimating equations from serum creatinine will not adequately assess renal function early after major heart surgery. To gain adequate information on renal function early after Htx, GFR needs to be measured, not estimated.

Three decades of heart transplantation: experience and long-term outcome

Objectives. Heart transplantation (HTx) has become an established treatment option in patients with end-stage heart failure. The aim of this study was to report on long-term outcome over the past three decades. Design. Consecutive adult patients receiving first-time and isolated HTx from October 3, 1990, to November 2, 2020, at Rigshospitalet, Copenhagen, Denmark, were retrospectively evaluated. Data were obtained from the Scandinavian Transplant Registry and patient medical records. Recipients were grouped by time of transplantation (early era: 1990-1999; mid era: 2000-2009; recent era: 2010-2020). Results. A total of 384 recipients (77% men, median age 50 [IQR: 40-57]) were included. Median number of HTx procedures per year was 12 (10-14). Overall, 22% of patients were bridged to HTx with a mechanical circulatory support device. Median survival for the whole cohort was 13.8 years and improved numerically from the early era (12.6 years) to the mid era (14.9 years). Median survival conditional on survival to 1-year follow-up after HTx was 16.1 years. Survival probability by Kaplan-Meier method improved significantly from the mid to the recent era (log-rank p = .02). Conclusions. Heart transplantation remains an excellent treatment for selected patients with end-stage heart failure and long-term outcome has improved significantly over the past decades.

Variation in Time to Peak Values for Different Lung Function Parameters After Double Lung Transplantation

BACKGROUND

Establishment of baseline values for forced expiratory volume in the first second (FEV₁), forced vital capacity (FVC), or total lung capacity (TLC) is required when diagnosing and phenotyping chronic lung allograft dysfunction after lung transplant. It is generally accepted that the baseline (peak) values of these parameters occur simultaneously, but this assumption has not been substantiated for TLC.

METHODS

All lung function measurements in all double lung transplant recipients from a single center in the period from 1992-2014 were included. Time to baseline FEV₁ was assessed according to standards from the International Society for Heart and Lung Transplantation, and time to peak FVC, TLC, and diffusion capacity for carbon monoxide were evaluated.

RESULTS

A total of 288 double lung transplants surviving more than 3 months after transplant were included. Baseline FEV₁ occurred at a median of 0.77 years post transplant and was statistically different from median times to the peak FVC (1.02 years), to peak TLC (1.37 years), and to peak diffusion capacity for carbon monoxide 1.04 years post transplant (all log-rank P < .001). At the time of baseline FEV1, FVC, and TLC were at a mean of 96% and 95% of their peak values, respectively.

CONCLUSION

The peak lung function is reached at different time points for different parameters post transplant with FEV₁ baseline occurring first. For most patients values of FVC and TLC obtained at time for baseline FEV₁ is a good estimate of peak values, but in a small percentage of patients this procedure may jeopardize phenotyping of chronic lung allograft dysfunction based solely on lung function parameters.

Vector Flow Imaging of the Ascending Aorta in Patients with Tricuspid and Bicuspid Aortic Valve Stenosis Treated with Biological and Mechanical Implants

Aortic valve stenosis (AS) is treated with biological prostheses (BPs) and mechanical prostheses (MPs). Vector flow imaging (VFI), an angle-independent ultrasound method, can quantify flow complexity (vector concentration (VC)) and secondary rotation (SR). Ten patients (mean age: 70.7 y) with tricuspid AS scheduled for BPs, 10 patients (mean age: 56.2 y) with bicuspid AS scheduled for MPs and 10 patients (mean age: 63.9 y) with normal aortic valves were scanned intra-operatively on the ascending aorta with VFI and conventional spectral Doppler. Bicuspid AS (peak systolic velocity (PSV): 380.9 cm/s, SR: 16.7 Hz, VC: 0.21) had more complex flow (p < 0.02) than tricuspid AS (PSV: 346.1 cm/s, SR: 17.1 Hz, VC: 0.33). Both groups had more complex and faster flow (p < 0.0001) than normal aortic valve patients (PSV: 124.0 cm/s, SR: 4.3 Hz, VC: 0.79). VC (r = 0.87) and SR (r = 0.89) correlated to PSV. After surgery, flow parameters changed (p < 0.0001) for patients with MPs (PSV: 250.4 cm/s, SR: 9.8 Hz, VC: 0.54) and BPs (PSV: 232.4 cm/s, SR: 12.5 Hz, VC: 0.61), with MPs having slower SR (p < 0.01). None of the implants had normal flow (p < 0.0001). In conclusion, VFI can provide new flow parameters for AS and implant assessment.

Lung transplantation after ex vivo lung perfusion in two Scandinavian centres

OBJECTIVES

We reviewed our combined clinical outcome in patients who underwent lung transplantation after ex vivo lung perfusion (EVLP) and compared it to the contemporary control group.

METHODS

At 2 Scandinavian centres, lungs from brain-dead donors, not accepted for donation but with potential for improvement, were subjected to EVLP (n = 61) and were transplanted if predefined criteria were met. Transplantation outcome was compared with that of the contemporary control group consisting of patients (n = 271) who were transplanted with conventional donor lungs.

RESULTS

Fifty-four recipients from the regular waiting list underwent transplantation with lungs subjected to EVLP (1 bilateral lobar, 7 single and 46 double). In the EVLP and control groups, arterial oxygen tension/inspired oxygen fraction ratio at arrival in the intensive care unit (ICU) was 30 ± 14 kPa compared to 36 ± 14 (P = 0.005); median time to extubation was 18 h (range 2-912) compared to 7 (range 0-2280) (P = 0.002); median ICU length of stay was 4 days (range 2-65) compared to 3 days (range 1-156) (P = 0.002); Percentage of expected forced expiratory volume at 1s (FEV1.0%) at 1 year was 75 ± 29 compared to 81 ± 26 (P = 0.18); and the 1-year survival rate was 87% [confidence interval (CI) 82-92%] compared to 83% (CI 81-85), respectively. Follow-up to a maximum of 5 years did not show any significant difference in survival between groups (log rank, P = 0.63).

CONCLUSIONS

Patients transplanted with lungs after EVLP showed outcomes comparable to patients who received conventional organs at medium-term follow-up. Although early outcome immediately after transplantation showed worse lung function in the EVLP group, no differences were observed at a later stage, and we consider EVLP to be a safe method for increasing the number of transplantable organs.

Pediatric Transthoracic Cardiac Vector Flow Imaging - A Preliminary Pictorial Study

Purpose Conventional pediatric echocardiography is crucial for diagnosing congenital heart disease (CHD), but the technique is impaired by angle dependency. Vector flow imaging (VFI) is an angle-independent noninvasive ultrasound alternative for blood flow assessment and can assess complex flow patterns not visible on conventional Doppler ultrasound.

Materials and Methods 12 healthy newborns and 3 infants with CHD were examined with transthoracic cardiac VFI using a conventional ultrasound scanner and a linear array.

Results VFI examinations revealed common cardiac flow patterns among the healthy newborns, and flow changes among the infants with CHD not previously reported with conventional echocardiography.

Conclusion For assessment of cardiac flow in the normal and diseased pediatric heart, VFI may provide additional information compared to conventional echocardiography and become a useful diagnostic tool.

High-dose methylprednisolone in video-assisted thoracoscopic surgery lobectomy: a randomized controlled trial

OBJECTIVES

The optimal postoperative analgesic strategy after video-assisted thoracoscopic surgery lobectomy remains undetermined. We hypothesized that high-dose preoperative methylprednisolone (MP) would improve analgesia compared to placebo.

METHODS

A total of 120 adult patients were randomized equally to 125 mg MP or placebo before the start of their elective video-assisted thoracoscopic surgery lobectomy. Group allocation was blinded to patients, investigators and caregivers, and all patients received standardized multimodal, opioid-sparing analgesia. Our primary outcome was area under the curve on a numeric rating scale from 0 to 10, for pain scores on the day of surgery and on postoperative days 1 and 2. Clinical follow-up was 2-3 weeks, and telephone follow-up was 12 weeks after surgery.

RESULTS

Ninety-six patients were included in the primary analysis. Methylprednisolone significantly decreased median pain scores on the day of surgery: at rest (numeric rating scale 1.6 vs 2.0, P = 0.019) and after mobilization to a sitting position (numeric rating scale 1.7 vs 2.5, P = 0.004) but not during arm abduction and coughing (P = 0.052 and P = 0.083, respectively). Nausea and fatigue were reduced on the day of surgery (P = 0.04 and 0.03), whereas no outcome was improved on postoperative Days 1 and 2. Methylprednisolone did not increase the risk of complications but increased blood glucose levels on the day of surgery (P < 0.0001).

CONCLUSIONS

High-dose preoperative MP significantly reduced pain at rest and after mobilization to a sitting position on the day of surgery, without later analgesic effects. Nausea and fatigue were improved without side effects, except transient higher postoperative blood glucose levels.

CLINICAL TRIAL REGISTRATION

Registered at clinicaltrialsregister.eu [7 November 2012, EudraCT 2012-004451-37; https://www.clinicaltrialsregister.eu/ctr-search/trial/2012-004451-37/DK].

[Extracorporeal cardiopulmonary resuscitation for patients with out-of-hospital refractory cardiac arrest]

Out-of-hospital cardiac arrest is associated with high mortality and morbidity. Treatment options remain few in refractory cases, but extracorporeal cardiopulmonary resuscitation (eCPR) is increasingly applied to improve the outcome. This article summarizes the use, experience and outcome of eCPR focussing on current knowledge of criteria for selection of relevant patients for treatment.

Aortic Valve Stenosis Increases Helical Flow and Flow Complexity: A Study of Intra-Operative Cardiac Vector Flow Imaging

Aortic valve stenosis alters blood flow in the ascending aorta. Using intra-operative vector flow imaging on the ascending aorta, secondary helical flow during peak systole and diastole, as well as flow complexity of primary flow during systole, were investigated in patients with normal, stenotic and replaced aortic valves. Peak systolic helical flow, diastolic helical flow and flow complexity during systole differed between the groups (p < 0.0001), and correlated to peak systolic velocity (R = 0.94, 0.87 and 0.88, respectively). The study indicates that aortic valve stenosis increases helical flow and flow complexity, which are measurable with vector flow imaging. For assessment of aortic stenosis and optimization of valve surgery, vector flow imaging may be useful.

Vector Flow Imaging Compared with Conventional Doppler Ultrasound and Thermodilution for Estimation of Blood Flow in the Ascending Aorta

Transverse oscillation (TO) is a real-time ultrasound vector flow method implemented on a commercial scanner. The TO setup was examined on a flowrig with constant and pulsatile flow. Subsequently, 25 patients undergoing cardiac bypass surgery were scanned intraoperatively with TO on the ascending aorta and compared to transesophageal echocardiography (TEE) and pulmonary artery catheter thermodilution (PACTD). On the flowrig, TO had a precision of 5.5%, 9.4% and 14.7%, a percentage error of 18.2%, 14.6% and 40.7%, and a mean bias of 0.4 cm/s, 36.8 ml/min and 32.4 ml/min for velocity and flow rate (constant and pulsatile) estimation. The correlation coefficients for all flowrig evaluations were 0.99 indicating systematic bias. After bias correction, the percentage error was reduced to 11.5%, 12.6% and 15.9% for velocity and flow rate (constant and pulsatile) estimation. In the in vivo setup, TO, TEE, and PACTD had a precision of 21.9%, 13.7%, and 12.0%. TO compared with TEE and PACTD had a mean bias of 12.6 cm/s and -0.08 l/min, and a percentage error of 23.4%, and 36.7%, respectively. The percentage error was reduced to 22.9% for the TEE comparison, but increased to 43.8% for the PACTD comparison, after correction for the systematic bias found in the flowrig. TO is a reliable and precise method for velocity and flow rate estimation on a flowrig. However, TO with the present setup, is not interchangeable with PACTD for cardiac volume flow estimation, but is a reliable and precise angle-independent ultrasound alternative for velocity estimation of cardiac flow.

Intra-Operative Vector Flow Imaging Using Ultrasound of the Ascending Aorta among 40 Patients with Normal, Stenotic and Replaced Aortic Valves

Stenosis of the aortic valve gives rise to more complex blood flows with increased velocities. The angle-independent vector flow ultrasound technique transverse oscillation was employed intra-operatively on the ascending aorta of (I) 20 patients with a healthy aortic valve and 20 patients with aortic stenosis before (IIa) and after (IIb) valve replacement. The results indicate that aortic stenosis increased flow complexity (p < 0.0001), induced systolic backflow (p < 0.003) and reduced systolic jet width (p < 0.0001). After valve replacement, the systolic backflow and jet width were normalized (p < 0.52 and p < 0.22), but flow complexity was not (p < 0.0001). Flow complexity (p < 0.0001), systolic jet width (p < 0.0001) and systolic backflow (p < 0.001) were associated with peak systolic velocity. The study found that aortic stenosis changes blood flow in the ascending aorta and valve replacement corrects some of these changes. Transverse oscillation may be useful for assessment of aortic stenosis and optimization of valve surgery.

Analysis of Systolic Backflow and Secondary Helical Blood Flow in the Ascending Aorta Using Vector Flow Imaging

Secondary rotational flow and systolic backflow are seen in the ascending aorta and, in this study, were analyzed with the vector velocity method transverse oscillation. Twenty-five patients were scanned intra-operatively, and the vector velocities were related to estimates of transesophageal echocardiography and pulmonary artery catheter thermodilution, and associated with gender, age, aortic diameter, atherosclerotic plaques, left ventricular ejection fraction and previous myocardial infarctions. Secondary flow was present for all patients. The duration and rotational frequency (p < 0.001) and the duration and flow direction of the secondary flow (p < 0.002) were associated. Systolic backflow was present in 40% of the patients and associated with systolic velocities (p < 0.002) and the presence of atherosclerotic plaques (p < 0.001). No other significant associations were observed. The study indicates that backflow is injurious and that secondary flow is a normal flow phenomenon. The study also shows that transverse oscillation can provide new information on blood flow in the ascending aorta.

Using clinical parameters to guide fluid therapy in high-risk thoracic surgery. A retrospective, observational study

Background

Despite extensive research, the debate continues as to the optimal way of guiding intraoperative and postoperative fluid therapy. In 2009 we changed our institutional guideline for perioperative fluid therapy in patients undergoing extrapleural pneumonectomy (EPP) and implemented the use of central venous oxygen saturation and intended low urine output to guide therapy in the early postoperative period. Here we evaluate the consequences of our changes.

Methods

Retrospective, observational study of 30 consecutive patients undergoing EPP; 18 who had surgery before and 12 who had surgery after the changes. Data were collected from patient files and from institutional databases. Outcome measures included: Volumes of administered fluids, fluid balances, length of stays and postoperative complications. Dichotomous variables were compared with Fisher’s exact test, whereas continuous variables were compared with Student’s unpaired t-test or the Wilcoxon Two-Sample Test depending on the distribution of data.

Results

The applied changes significantly reduced the volumes of administered fluids, both in the intraoperative (p = 0.01) and the postoperative period (p = 0.04), without increasing the incidence of postoperative complications. Mean length of stay in the intensive care unit (LOSI) was reduced from three to one day (p = 0.04) after the changes.

Conclusion

The use of clinical parameters to balance fluid restriction and a sufficient circulation in patients undergoing EPP was associated with a reduction in mean LOSI without increasing the incidence of postoperative complications. Due to methodological limitations these results are only hypothesis generating.

First report on intraoperative vector flow imaging of the heart among patients with healthy and diseased aortic valves

The vector velocity method Transverse Oscillation (TO) implemented on a conventional ultrasound (US) scanner (ProFocus, BK Medical, Herlev, Denmark) can provide real-time, angle-independent estimates of the cardiac blood flow. During cardiac surgery, epicardial US examination using TO was performed on (A) 3 patients with healthy aortic valve and (B) 3 patients with aortic valve stenosis. In group B, the systolic flow of the ascending aorta had higher velocities, was more aliased and chaotic. The jet narrowed to 44% of the lumen compared to 75% in group A and with a vector concentration, a measure of flow complexity, of 0.41 compared to 0.87 in group A. The two groups had similar secondary flow of the ascending aorta with an average rotation frequency of 4.8 Hz. Simultaneous measurements were obtained with spectral Doppler (SD) and a thermodilution technique (TD). The mean difference in peak systolic velocity compared to SD in group A was 22% and 45% in B, while the mean difference in volume flow compared to TD in group A was 30% and 32% in B. TO can potentially reveal new information of cardiac blood flow, and may become a valuable diagnostic tool in the evaluation of patients with cardiovascular diseases.

First Danish experience with ex vivo lung perfusion of donor lungs before transplantation

INTRODUCTION

The number of lung transplantations is limited by a general lack of donor organs. Ex vivo lung perfusion (EVLP) is a novel method to optimise and evaluate marginal donor lungs prior to transplantation. We describe our experiences with EVLP in Denmark during the first year after its introduction.

MATERIAL AND METHODS

The study was conducted by prospective registration of donor offers and lung transplantations in Denmark from 1 May 2012 to 30 April 2013. Donor lungs without any contraindications were transplanted in the traditional manner. Taken for EVLP were donor lungs that were otherwise considered transplantable, but failed to meet the usual criteria due to possible contusions or because they were from donors with sepsis or unable to pass the oxygenation test.

RESULTS

In the study period, seven of 33 Danish lung transplantations were made possible due to EVLP. One patient died of non-EVLP-related causes, but all other recipients were alive with normal graft function at the end of our registration period. All lungs showed an improved PaO2/FiO2 ratio from a median 23.1 kPa (8.8-38.9) within the donor to 58.8 kPa (34.9-76.5) (FiO2 = 1.0) after EVLP, which corresponds to a 155% improved oxygenation. The median time to extubation, time in intensive care unit and the admission period were 1, 7 and 39 days, respectively.

CONCLUSION

In the first year after the introduction of EVLP in Denmark, seven pairs of donor lungs that previously would have been rejected have been transplanted as a result of their improved function. EVLP seems to be a safe way to increase the use of marginal donor lungs.

FUNDING

no funding was granted for the present paper.

TRIAL REGISTRATION

not relevant.

Intraoperative cardiac ultrasound examination using vector flow imaging

Conventional ultrasound (US) methods for blood velocity estimation only provide one-dimensional and angle-dependent velocity estimates; thus, the complexity of cardiac flow has been difficult to measure. To circumvent these limitations, the Transverse Oscillation (TO) vector flow method has been proposed. The vector flow method implemented on a commercial scanner provided real-time, angle-independent estimates of cardiac blood flow. Epicardiac and epiaortic, intraoperative US examinations were performed on three patients with stenosed coronary arteries scheduled for bypass surgery. Repeating cyclic beat-to-beat flow patterns were seen in the ascending aorta and pulmonary artery of each patient, but these patterns varied between patients. Early systolic retrograde flow filling the aortic sinuses was seen in the ascending aorta as well as early systolic retrograde flow in the pulmonary artery. In diastole, stable vortices in aortic sinuses of the ascending aorta created central antegrade flow. A stable vortex in the right atrium was seen during the entire heart cycle. The measurements were compared with estimates obtained intraoperatively with conventional spectral Doppler US using a transesophageal and an epiaortic approach. Mean differences in peak systole velocity of 11% and 26% were observed when TO was compared with transesophageal echocardiography and epiaortic US, respectively. In one patient, the cardiac output derived from vector velocities was compared with pulmonary artery catheter thermodilution technique and showed a difference of 16%. Vector flow provides real-time, angle-independent vector velocities of cardiac blood flow. The technique can potentially reveal new information of cardiovascular physiology and give insight into blood flow dynamics.

Mechanism of injury and microbiological flora of the geographical location are essential for the prognosis in soldiers with serious warfare injuries

INTRODUCTION

Denmark has been engaged in the Afghanistan war and as a result, Rigshospitalet has received a number of multi-traumatized Danish soldiers. Lesions sustained in armed conflict differ from their civilian counterparts and knowledge of the pathophysiology related to these types of lesions is essential when engaging in the intensive care of these patients.

MATERIAL AND METHODS

The study was conducted as a retrospective survey of Danish soldiers evacuated from Afghanistan to the Intensive Care Unit at Rigshospitalet in the 2002-2012 period. The following data were recorded: age, gender, hospitalization (days), mortality, organ involvement, respiratory therapy, dialysis, circulatory supportive care, antibiotic treatment and bacteriology. Furthermore, Acute Physiology and Chronic Health Evaluation, Simplified Acute Physiology Score and Sequential Organ Failure Assessment scores were calculated.

RESULTS

A total of twenty patients were identified and included in the study. All patients had sustained serious blast injuries as a result of explosion. Primarily the central nervous system, respiratory, musculoskeletal and abdominal systems were affected by the explosions. Eighteen patients survived to discharge and two patients died.

DISCUSSION

Explosion was the most frequent cause of injury in all cases and caused damage to several organ systems. Infections after combat injuries are a major problem because of the different microbiological profile.

CONCLUSION

The use of explosives has been and remains a substantial part of warfare, and this review has showed us that the knowledge of the mechanism of injury is indeed essential, and that intelligence on the microbiological flora of the geographical location of the conflict is essential.

FUNDING

not relevant.

TRIAL REGISTRATION

not relevant.

[Fatal course of a patient during in vitro fertilisation treatment]

Chylomicronaemia syndrome is a rare disorder primarily caused by a genetic defect which increases triglycerides, combined with a secondary inducing factor. We describe the fatal course of a 33-year-old, pregnant woman with known dyslipidaemia who had been treated with in vitro fertilisation and developed chylomicronaemia syndrome with severe hypertriglyceridaemia, hypertriglyceridaemia-induced acute pancreatitis and septic shock. Appropriate treatment including close monitoring, severe restriction of dietary fat intake and early plasmapheresis is emphasized - especially during pregnancy.