Influence of left ventricular assist device pressure-flow characteristic on exercise physiology: Assessment with a verified numerical model

Current left ventricular assist devices are designed to reestablish patient's hemodynamics at rest but they lack the suitability to sustain the heart adequately during physical exercise. Aim of this work is to assess the performance during exercise of a left ventricular assist device with flatter pump pressure-flow characteristic and increased pressure sensitivity (left ventricular assist device 1) and to compare it to the performance of a left ventricular assist device with a steeper characteristic (left ventricular assist device 2). The two left ventricular assist devices were tested at constant rotational speed with a verified computational cardiorespiratory simulator reproducing an average left ventricular assist device patient response to exercise (EXE↑) and a left ventricular assist device patient with no chronotropic and inotropic response (EXE→). According to the results, left ventricular assist device 1 pumps a higher flow than left ventricular assist device 2 both at EXE↑ (6.3 vs 5.6 L/min) and at EXE→ (6.7 vs 6.1 L/min), thus it better unloads the left ventricle. Left ventricular assist device 1 increases the power delivered to the circulation from 0.63 W at rest to 0.67 W at EXE↑ and 0.82 W at EXE→, while left ventricular assist device 2 power shows even a minimal decrease. Left ventricular assist device 1 better sustains exercise hemodynamics and can provide benefits in terms of exercise performance, especially for patients with a poor residual left ventricular function, for whom the heart can hardly accommodate an increase of cardiac output.

Improvement of Survival Rate in Patients with Cardiogenic Shock by Using Nonpulsatile and Pulsatile Ventricular Assist Device

Between January 1988 and January 1992, 65 patients (pts) had a ventricle assist device (VAD) inserted in our clinic. In 24 pts a VAD was applied because of primarily unsuccessful weaning from cardiopulmonary bypass (Group A). In a further 24 pts (Group B) a VAD was installed for the therapy of refractive cardiogenic shock (CS) after initially successful cardiac surgery (n=21) and after acute myocardial infarction (n=3). Twelve pts were bridged to heart transplantation (Group C) and five had a VAD inserted for various other reasons (Group D). In 36 (55.4%) of the total 65 pts a nonpulsatile VAD (Biomedicus® 540) was used: 10 in Group A; 20 in B, 3 in C and 3 in D. In 29 pts (44.6%) a pulsatile VAD (Abiomed® BVS 5000) was used: 14 in Group A, 4 in B, 9 in C and 2 in D. Weaning rate and long-term survival rates were 50% and 46% respectively in Group A and 38% and 42% in Group B. Seven pts from Group C were transplanted and six are long-term survivors. Two pts (40%) in Group D were discharged from hospital. Major postoperative complications were bleeding (46%), thromboembolism (14%), multiple organ failure (11%), renal failure (11%), arterial embolism (4.6%), sepsis (3%). The results indicate that application of a VAD can be recommended in pts with postcardiotomy CS to allow recovery of cardiac function and in pts with irreversible ventricular damage as bridging to HTX.

Mechanical ventricular support using pulsatile Abiomed BVS 5000 and centrifugal Biomedicus-pump in postcardiotomy shock

Since we started using ventricular assist devices (VAD) in July 1987 up to August 1993, 63 of 15,650 (0.4%) patients (pts) who underwent open heart sugery were supported postoperatively by VAD at out institution. Forty-three were male and 20 female, mean age 55.5 years. In 49 pts coronary artery bypass grafting (CABG), in 8 pts valve surgery, in 3 pts combined CABG and valve surgery and in 3 pts corrective procedures for congenital heart disease were performed. Perioperative myocardial infarction was the most frequent indication (73%). In 37 of the 63 pts (58.7%) a centrifugal (Biomedicus pump (group A) was used and in 26 pts (41.3%) a pulsatile Abiomed BVS 5000 (group B). Fourteen of 37 pts (38%) in group A were weaned from the VAD and all of them were discharged. Twenty-three pts were unable to be weaned and 19 of these pts died. The remaining 4 pts were transplanted successfully and subsequently 3 died and 1 was discharged. In all, 15 pts (39%) were long-term survivors. Sixteen of 26 pts (62%) in group B were weaned from VAD and 13 (50%) of them were discharged of whom 3 died. Ten patients were unable to be weaned and 7 of these died. The remaining 3 pts were transplanted successfully. In all, 16 pts (61.5%) were long-term survivors. The shorter the interval between beginning resuscitation and application of VAD the better the outcome. Younger age, VAD installation in OR, support time between 2 and 7 days and Abiomed pump, influence the survival rate positively. Because of higher recovery and survival rates in patients assisted by Abiomed compared to the Biomedicus pump, we recommend the Abiomed pump in postcardiotomy cardiac failure.

The MiniACcor: Constructive Redesign of an Implantable Total Artificial Heart, Initial Laboratory Testing and Further Steps

The Aachen Total Artificial Heart (ACcor) has been under development at the Helmholtz Institute in Aachen over the last decade. It may serve as a bridge to transplant or as a long-term replacement of the natural heart. Based upon previous in vivo experiments with the ACcor total artificial heart, it was decided to optimize and redesign the pump unit. Smaller dimensions, passive filling and separability into three components were the three main design goals. The new design is called the MiniACcor, which is about 20% smaller than its predecessor, and weighs only 470 grams. Also its external driver/control unit was miniaturized and a new microcontroller was selected. To validate the design, it was extensively tested in laboratory mock loops. The MiniACcor was able to pump between 4.5 and 7 l/min at different pump rates against normal physiological pressures. Several requirements for the future compliance chamber and transcutaneous energy transmission (TET) system were also measured in the same mock loop. Further optimization and validation are being performed in cooperation with the Heart and Diabetes Centre North Rhine-Westphalia.

Radical Pericardiectomy for Chronic Constrictive Pericarditis

A retrospective analysis was undertaken in 79 patients who underwent pericardiectomy for chronic constrictive pericarditis from January 1985 to February 1999. Most operations (77) were carried out with cardiopulmonary bypass, with subtotal pericardiectomy in 75 patients, and concomitant operations in 25. Postoperative complications occurred in 8 patients: cerebrovascular accident in 2, renal insufficiency in 5, bleeding in 2, low output syndrome in 4, and respiratory insufficiency in 2. The operative mortality was 5%; causes of death were cardiac-related in all cases. Actuarial survival at 1, 5, and 10 years was 89.9% ± 3.4%, 74.9% ± 5.7%, and 55.4% ± 13.5%, respectively. Regression analysis was performed using 53 clinical variables. Female gender, renal insufficiency, concomitant coronary artery bypass grafting, and preoperative right ventricular end-diastolic pressure > 20 mm Hg were found to be predictors of poor survival. At follow-up, improved functional status was noted in 88% of patients. Subtotal pericardiectomy can be performed on cardiopulmonary bypass with low mortality and good long-term survival.

Successful correction of a total anomalous venous connection in a 63-year-old male--case report and review of the literature

Total anomalous pulmonary venous connection is a rare variant of cyanotic congenital heart disease and usually requires surgical correction within the first few months of life. We report midterm results of a 63-year-old male with intracardiac total anomalous venous return into the coronary sinus who presented with congestive predominantly right heart failure and underwent corrective surgery with unroofing of the coronary sinus and patch closure of the secundum atrial septal defect.

Global gene expression analysis in nonfailing and failing myocardium pre- and postpulsatile and nonpulsatile ventricular assist device support

Mechanical unloading by ventricular assist devices (VAD) leads to significant gene expression changes often summarized as reverse remodeling. However, little is known on individual transcriptome changes during VAD support and its relationship to nonfailing hearts (NF). In addition no data are available for the transcriptome regulation during nonpulsatile VAD support. Therefore we analyzed the gene expression patterns of 30 paired samples from VAD-supported (including 8 nonpulsatile VADs) and 8 nonfailing control hearts (NF) using the first total human genome array available. Transmural myocardial samples were collected for RNA isolation. RNA was isolated by commercial methods and processed according to chip-manufacturer recommendations. cRNA were hybridized on Affymetrix HG-U133 Plus 2.0 arrays, providing coverage of the whole human genome Array. Data were analyzed using Microarray Analysis Suite 5.0 (Affymetrix) and clustered by Expressionist software (Genedata). We found 352 transcripts were differentially regulated between samples from VAD implantation and NF, whereas 510 were significantly regulated between VAD transplantation and NF (paired t-test P < 0.001, fold change ≥1.6). Remarkably, only a minor fraction of 111 transcripts was regulated in heart failure (HF) and during VAD support. Unsupervised hierarchical clustering of paired VAD and NF samples revealed separation of HF and NF samples; however, individual differentiation of VAD implantation and VAD transplantation was not accomplished. Clustering of pulsatile and nonpulsatile VAD did not lead to robust separation of gene expression patterns. During VAD support myocardial gene expression changes do not indicate reversal of the HF phenotype but reveal a distinct HF-related pattern. Transcriptome analysis of pulsatile and nonpulsatile VAD-supported hearts did not provide evidence for a pump mode-specific transcriptome pattern.

HeartMate II ventricular assist device thrombosis-an echocardiographic approach to diagnosis: can Doppler evaluation of flow be useful?

A 68-year-old man was admitted to the hospital 4 months after HeartMate II ventricular assist device implantation, because his clinical status had deteriorated and his levels of lactate dehydrogenase and free hemoglobin had increased. Transthoracic echocardiography performed at admission revealed decreased basic diastolic continuous flow velocity with a pulsatile increase in flow velocity during ventricular contraction in both inflow and outflow cannulas. Twelve hours after beginning lytic therapy, basal diastolic continuous flow velocity had increased, and the amplitude between diastolic and systolic flow velocity had decreased. The clinical status of the patient improved, and his lactate dehydrogenase decreased. A decrease in basal diastolic flow may be a valuable marker of flow disturbance in continuous flow ventricular assist devices.

Extracorporeal life support in pediatric patients with congenital heart diseases: outcome of a single centre

AIM

In pediatric patients with congenital heart disease low cardiac output (LCO) is the principal complication after corrective heart surgery. In LCO refractory to all therapeutic options, mechanical circulatory support is the final method to keep these patients alive. In this present study the authors reviewed the outcome of pediatric patients who required mechanical circulatory support after corrective surgery with extracorporeal membrane oxygenation or ventricle assisted devices (VAD).

METHODS

A retrospective single centre consecutive cohort study was carried out in children who required different mechanical circulatory support indicated by postcardiotomy low output syndrome between 1991 and 2004. A total of 20 patients received extracorporeal life support. The indications for surgery were: 12 transposition of great arteries, 1 Bland-White-Garland syndrome, 3 tetralogy of Fallot, 1 hypoplasia of aortic arch, 1 total anomalous pulmonary vein connection, and 2 ventricle septum defect.

RESULTS

Mean age was 1.29 years. Mean duration of assist was 8.87 days. Seven patients out of 20 survived, six could be discharged after myocardial recovery from LCO and one could be discharged after successful heart transplantation. The overall mortality in patients with extracorporeal life support was 65%. The causes of death were multiorgan failure and bleeding in one case was a VAD related complication.

CONCLUSION

The use of extracorporeal life support (ECLS) shows a high mortality rate. However, ECLS can still help to keep some of those patients alive. Mechanical support devices are the ultimate chance to save time, to increase survival and to bridge the time until heart transplantation.

23S rDNA real-time polymerase chain reaction of heart valves: a decisive tool in the diagnosis of infective endocarditis

AIMS

A new diagnostic strategy to improve the detection of pathogens in heart valves (HVs) from patients with infective endocarditis (IE) was evaluated.

METHODS AND RESULTS

Three hundred and fifty seven HVs surgically removed from 326 patients with proven IE or suspicious intra-operative findings, examined by 16S rDNA polymerase chain reaction (PCR) and culture were retrospectively analysed according to the predictive value of various PCR methods. Patients were classified into four categories: active IE, IE with ambiguous infective status, healed IE, and valve diseases but no IE. Retained samples of 200 HVs were analysed by real-time PCR targeting bacterial 23S rDNA, fungal 28S rDNA, and mycoplasmal tuf gene. 16S rDNA PCR revealed 80.6% sensitivity, 100% specificity, 100% positive predictive value, and 71% negative predictive value (NPV), compared with cultivation with 33.4, 96.6, 95.5, and 40.9%, respectively. The use of real-time PCR increased diagnostic sensitivity to 96.4%, and NPV to 92.5%. Bacterial load, C-reactive protein, and white blood cell counts (WBCs) decreased during antibiotic treatment. Bacterial load showed no correlation to C-reactive protein or WBCs, whereas C-reactive protein and WBCs were significantly correlated.

CONCLUSION

23S rDNA real-time PCR of surgically removed HVs improves the diagnosis of IE. Polymerase chain reaction analysis of explanted HVs allow the optimization of the antimicrobial therapy, especially in patients with culture-negative IE.

Surgical treatment of left ventricular aneurysm

When a left ventricular aneurysm leads to pulmonary congestive symptoms, aneurysmectomy may provide relief. This retrospective study included 269 patients who underwent aneurysmectomy between 1993 and 2002, by the classic Cooley operation in 164 and by Dor ventriculoplasty in 105. There were no significant differences in early and late survival between groups, although the frequency of extended anteroseptal infarction was higher in patients undergoing the Dor procedure. Postoperative echocardiographic findings showed significant improvements in left ventricular function in both groups, in terms of end-diastolic and end-systolic dimensions and ejection fraction. Left ventricular aneurysmectomy significantly improved the clinical status and hemodynamic parameters of symptomatic patients. The choice of surgical technique depends on the extent of the scar segment, especially the presence of an anteroseptal scarred area. The Dor procedure is more suitable for restoring normal left ventricular geometry in patients with extensive septal infarction.

K201 improves aspects of the contractile performance of human failing myocardium via reduction in Ca2+ leak from the sarcoplasmic reticulum

In heart failure, intracellular Ca2+ leak from cardiac ryanodine receptors (RyR2s) leads to a loss of Ca2+ from the sarcoplasmic reticulum (SR) potentially contributing to decreased function. Experimental data suggest that the 1,4-benzothiazepine K201 (JTV-519) may stabilise RyR2s and thereby reduce detrimental intracellular Ca2+ leak. Whether K201 exerts beneficial effects in human failing myocardium is unknown. Therefore, we have studied the effects of K201 on muscle preparations from failing human hearts. K201 (0.3 microM; extracellular [Ca2+]e 1.25 mM) showed no effects on contractile function and micromolar concentrations resulted in negative inotropic effects (K201 1 microM; developed tension -9.8 +/- 2.5% compared to control group; P < 0.05). Interestingly, K201 (0.3 microM) increased the post-rest potentiation (PRP) of failing myocardium after 120 s, indicating an increased SR Ca2+ load. At high [Ca2+]e concentrations (5 mmol/L), K201 increased PRP already at shorter rest intervals (30 s). Strikingly, treatment with K201 (0.3 microM) prevented diastolic dysfunction (diastolic tension at 5 mmol/L [Ca2+]e normalised to 1 mmol/L [Ca2+]e: control 1.26 +/- 0.06, K201 1.01 +/- 0.03, P < 0.01). In addition at high [Ca2+]e) K201 (0.3 microM) treatment significantly improved systolic function [developed tension +27 +/- 8% (K201 vs. control); P < 0.05]. The beneficial effects on diastolic and systolic functions occurred throughout the physiological frequency range of the human heart rate from 1 to 3 Hz. Upon elevated intracellular Ca2+ concentration, systolic and diastolic contractile functions of terminally failing human myocardium are improved by K201.

Reconstructive surgery for an akinetic anterior ventricular wall in ischemic cardiomyopathy

BACKGROUND

The purpose of this prospective study is to analyze the postoperative outcome after only left ventricular reconstruction (LVR) versus LVR combined with coronary artery bypass grafting (CABG) and/or mitral valve (MV) procedure in ischemic cardiomyopathy (ICM) as a result of an akinetic anterior ventricular wall.

METHODS AND RESULTS

Nineteen patients underwent only LVR, and 37 underwent a concomitant LVR procedure. In both groups, New York Heart Association (NYHA) classification improved significantly from 3.5 +/- 0.6 to 2.2 +/- 0.5 (LVR group) and 3.4 +/- 0.7 to 2.5 +/- 0.5 (combined LVR group). Ejection fraction improved significantly from 25.1 +/- 3.2 to 35.3 +/- 4.5% in the LVR group and 28.1 +/- 2.2 to 37.6 +/- 5.5% in the combined LVR group. Cardiac index improved significantly from 1.8 +/- 0.6 to 2.3 +/- 0.5 l/min/m2 in the LVR group and 1.6 +/- 0.4 to 2.2 +/- 0.6 l/min/m2 in the combined LVR group. An additional concomitant procedure increased the mortality rate only slightly. The overall 1- and 5-year actuarial survival rates were 90% and 75% in the LVR group and 80% and 70% in the combined LVR group.

CONCLUSIONS

The LVR for akinetic ventricular wall shows very satisfactory early and long-term results. The LVR, with or without concomitant procedures, has considerable benefits for operative therapy.

Heat shock protein 27 modification is increased in the human diabetic failing heart

Chronic conditions like diabetes mellitus (DM) leading to altered metabolism might cause cardiac dysfunction. Hyperglycemia plays an important role in the pathogenesis of diabetic complications including accumulation of methylglyoxal (MG), a highly reactive alpha-dicarbonyl metabolite of glucose degradation pathways and increased generation of advanced glycation endproducts (AGEs). The aim of this investigation was to study the extent of the MG-modification argpyrimidine in human diabetic heart and in rat cardiomyoblasts grown under hyperglycemic conditions. Left ventricular myocardial samples from explanted hearts of patients with cardiomyopathy with (n=8) or without DM (n=8) as well as nonfailing donor organs (n=6), and rat cardiac myoblasts H9c2 treated with glucose were screened for the MG-modification argpyrimidine. The small heat shock protein 27 (Hsp27) revealed to be the major argpyrimidine containing protein in cardiac tissue. Additionally, the modification of arginine leading to argpyrimidine and the phosphorylation of Hsp27 are increased in the myocardium of patients with DM. In H9c2 cells hyperglycemia leads to a decrease of the Hsp27-expression and an increase in argpyrimidine content and phosphorylation of Hsp27, which was accompanied by the induction of oxidative stress and apoptosis. This study shows an association between diabetes and increased argpyrimidine-modification of myocardial Hsp27, a protein which is involved in apoptosis, oxidative stress, and cytoskeleton stabilization.

Valve replacement in octogenarians: arguments for an earlier surgical intervention

BACKGROUND AND AIM OF THE STUDY

In octogenarians with symptomatic aortic valve stenosis (AS), aortic valve replacement (AVR) is frequently not performed in due time, because the prognostic benefit is underestimated, while perioperative morbidity and mortality are overestimated. The severely impaired prognosis and quality of life after myocardial decompensation then urges AVR with a significantly increased perioperative risk.

METHODS

Between 2003 and 2006, all octogenarians with isolated symptomatic AS (indexed aortic valve opening area <0.5 cm2/m2) referred to the authors' unit were prospectively included in the survey. Among the 83 patients enrolled (51 women, 32 men; mean age 84 +/- 5.1 years), 38 patients (26 women, 12 men; mean age 84 +/- 2.3 years) had signs of chronic myocardial decompensation (dilated left ventricle and/or reduced left ventricular function; left ventricular ejection fraction (LVEF) 43 +/- 18% (range: 25-53%). These patients comprised group A. All other patients (group B) had normal left ventricular dimensions, a normal LVEF (>55%), and no clinical episodes of myocardial decompensation. All patients underwent AVR, while 23 (28%) underwent simultaneous coronary revascularization.

RESULTS

In group A, the 30-day mortality rate was 5.3% (n = 2). Octogenarians without chronic myocardial decompensation had a lower 30-day mortality (1/45; 2.2%). The incidences of major postoperative complications (reversible acute renal failure, stroke, mechanical circulatory support) were significantly higher in group A (26.3% versus 8.9%, p < 0.05). During late follow up (mean 24.2 +/- 12.8 months), another four patients in group A (11.1%) and five in group B (11.4%) died. Octogenarians in group B had a significantly (p < 0.01) more favorable cumulative survival rate (87% versus 78% after 24 months; 81% versus 68% after 46 months).

CONCLUSION

AVR can be performed in octogenarians with a low mortality and morbidity, but should not be postponed. The decision to perform for AVR may take into consideration any life-limiting comorbidities, but should be made independent of the patient's age.

[The impact of diabetes mellitus on the results of coronary artery bypass grafting with respect to left ventricular function]

BACKGROUND

Diabetes mellitus is not only an independent risk factor for the development of arteriosclerosis, but also a risk factor for the surgical and interventional treatment of coronary artery disease (CAD).

PATIENTS AND METHODS

In 2003, a consecutive series of 2,142 patients underwent isolated coronary bypass grafting at the authors' institution, 567 of these suffering from diabetes mellitus.

RESULTS

An analysis of the diabetic and nondiabetic patients revealed a more pronounced risk profile, a significantly reduced left ventricular function and a significantly poorer quality of the coronary arteries in the diabetic group. Perioperative mortality in both groups was not different. The incidence of wound infections, renal failure and neurologic complications was much higher in diabetic patients.

CONCLUSION

From these findings it can be concluded that coronary artery bypass grafting in the current era is not associated with a higher perioperative mortality in diabetic patients despite their risk profile at baseline. The risk of wound infections and perioperative renal and neurologic complications is much higher in diabetic patients.

Genomic profiling of developing cardiomyocytes from recombinant murine embryonic stem cells reveals regulation of transcription factor clusters

Cardiomyocytes derived from pluripotent embryonic stem cells (ESC) have the advantage of providing a source for standardized cell cultures. However, little is known on the regulation of the genome during differentiation of ESC to cardiomyocytes. Here, we characterize the transcriptome of the mouse ESC line CM7/1 during differentiation into beating cardiomyocytes and compare the gene expression profiles with those from primary adult murine cardiomyocytes and left ventricular myocardium. We observe that the cardiac gene expression pattern of fully differentiated CM7/1-ESC is highly similar to adult primary cardiomyocytes and murine myocardium, respectively. This finding is underlined by demonstrating pharmacological effects of catecholamines and endothelin-1 on ESC-derived cardiomyocytes. Furthermore, we monitor the temporal changes in gene expression pattern during ESC differentiation with a special focus on transcription factors involved in cardiomyocyte differentiation. Thus, CM7/1-ESC-derived cardiomyocytes are a promising new tool for functional studies of cardiomyocytes in vitro and for the analysis of the transcription factor network regulating pluripotency and differentiation to cardiomyocytes.

Preoperative haemostasis testing does not predict requirement of blood products in cardiac surgery

OBJECTIVE

Standard haemostasis screening tests are performed to reveal unknown congenital or acquired disturbances of plasma and/or platelet haemostasis. Since their diagnostic efficacy is often low, routinely performed haemostasis testing has been questioned. We investigated whether preoperatively assessed haemostasis testing can be used to predict the requirement of blood products.

METHODS

We retrospectively assessed haemostasis parameters including platelet function testing by PFA 100 as well as the numbers of red blood cell (RBC) concentrates, fresh frozen plasmas (FFPs), and platelet concentrates (PCs) that were given peri-operatively and during the first two postoperative days in 2,831 cardiac surgery patients. Logistic regression analyses were used to select those parameters, which could predict blood product requirement.

RESULTS

Of our study cohort, 56.5% needed RBCs, 15% FFPs, and 5% PCs. The need for RBCs was associated with significantly altered pre-operative values of most haemostasis parameters. However, by the use of logistic regression analysis fibrinogen was the only haemostasis parameter that was independently associated with the use of RBCs (odds ratio 1.56; 95% CI: 1.27-1.91; P <0.001). The predictive value of other parameters such as age, body weight, haemoglobin, and haematocrit was however much higher in comparison to fibrinogen (odds ratios: 1.92-3.50; P <0.001). It was not possible to develop a score based on haemostasis parameters to accurately identify patients at risk for RBC use. Moreover, we were unable to estimate the need for FFPs and PCs using preoperative haemostasis testing.

CONCLUSIONS

Our data demonstrate that preoperatively performed haemostasis testing is not predictive in estimating the need for blood products in cardiac surgery patients.

Elevated afterload, neuroendocrine stimulation, and human heart failure increase BNP levels and inhibit preload-dependent SERCA upregulation

BACKGROUND

In heart failure, brain-type natriuretic peptide (BNP) is elevated and the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) downregulated. We previously showed that preload-induced SERCA-upregulation is suppressed by exogenous BNP.

METHODS AND RESULTS

Here we tested the hypothesis that afterload and neurohumoral activation would counterregulate preload-dependent SERCA upregulation through BNP, which finally results in decreased SERCA levels. We studied the effects of 6 hours preload, afterload, and isoproterenol stimulation on BNP and SERCA mRNA expression in rabbit and human failing muscles strips. Preload resulted in a pronounced upregulation of SERCA by 149% (isotonic versus slack, P<0.01). This upregulation was largely suppressed in afterloaded muscles (isometric versus slack: +32%; P<0.05). Similarly, presence of isoproterenol prevented SERCA upregulation in isotonic muscles. Afterload and isoproterenol resulted in a pronounced increase in BNP expression compared with slack by 225% (P<0.05) and 198% (P<0.01), respectively. Isoproterenol also increased expression of phospholamban by 84% (P<0.01). SERCA upregulation in preloaded muscles is associated with frequency-dependent potentiation of contractile force, which is absent in afterloaded muscles. In failing human myocardium, BNP expression was upregulated compared with nonfailing (+631%; P<0.05). Neither unloading nor preload or afterload induced a change in SERCA or BNP expression after 6 hours.

CONCLUSIONS

Afterload and neuroendocrine stimulation increase BNP expression thereby causing inhibition of preload-dependent SERCA upregulation. In failing human myocardium, high BNP expression may underlie the loss of preload-dependent upregulation of SERCA. BNP may thus contribute to adverse myocardial remodelling in heart failure.

Prevalent platelet dysfunction in patients with aortic valve disease

BACKGROUND AND AIM OF THE STUDY

In patients with heart valve disease, the valve leaflets display a gapped, rough endothelial lining often covered with calcified areas. As a consequence, blood flow is disturbed and a stimulation of components of the hemostasis system is assumed. The possible mechanisms of this process are, however, unclear at present.

METHODS

Platelet function was studied in 660 patients considered for isolated coronary artery bypass graft (CABG) surgery, and in 421 patients considered for single aortic valve replacement (AVR). Platelet function was monitored preoperatively using the platelet function analyzer device (PFA-100). The test results were reported as closure time of the membrane hole at the end of a capillary tube. The von Willebrand factor antigen, and its collagen-binding activity, were also determined among subgroups of 40 AVR and 50 CABG candidates.

RESULTS

Platelet dysfunction was displayed by only 22% of CAD patients, but by 83% of AVR candidates. The mean PFA closure time in AVR patients was considerably higher than in CAD patients (231 +/- 59 s versus 153 +/- 60 s, respectively; p < 0.01). The mean platelet volume, platelet distribution width and von Willebrand factor collagen binding and antigen levels did not differ between the patient groups.

CONCLUSION

It is assumed that, due to disturbed flow and shear exposition, following an initial activation, the platelets are partially degranulated, shed microparticles, and might become involved in the pathogenesis of microvascular dysfunction and thrombotic events in patients with aortic valve disease.

Significant obstruction of the right and left ventricular outflow tract in a patient with biventricular hypertrophic cardiomyopathy

Echocardiography demonstrated pronounced asymmetric left ventricular (LV) hypertrophy and thickened right ventricular muscular components in a 54-year-old woman with a history of dyspnoea (NYHA III), and recurrent syncopes. Left ventricular outflow peak gradient was 80 mmHg at rest and 125 mmHg during Valsalva manoeuvre. Cardiac cine and gadolinium-enhanced T1 weighted magnetic resonance imaging (MRI) provided striking images of a right ventricular outflow tract obstruction and a markedly abnormal gadolinium uptake in the interventricular septum consistent with myocardial fibrosis. Right and left heart catherization, with simultaneous measurement of aortic and LV pressures revealed a 150 mmHg subaortic gradient and a 130 mmHg subpulmonic gradient at rest. Impediment to right ventricular (RV) outflow was due to massive hypertrophy of the crista supraventricularis with an 'hour-glass' deformity. A surgical intervention with LV septal myotomy-myectomy and RV ventriculotomy was performed successfully. Hypertrophic obstructive cardiomyopathy with significant RV and LV outflow tract obstruction is a very rare finding. Echocardiography and MRI can be used in combination for non-invasive evaluation of morphological and haemodynamic information because mechanisms of obstruction are different in each ventricle.

[A telemetrically-guided program for weight reduction in overweight subjects (the SMART study)]

BACKGROUND AND OBJECTIVE

Compliance with weight reducing programs can be improved by intensive care and control. We tested a telemetrically-guided weight reduction program in overweight and obese persons.

PATIENTS AND METHODS

200 outpatients (62 males) with a mean body mass index of 34 kg/m (2) and a mean age of 47 years participated in a prospective study for one year. During the first six months, telemetrical support (weight-transmission via Bluetooth (short range)-technology, 20-minutes telephone consultation with a nutritionist) was given weekly. After six months, participants were randomly assigned either to a group with further telemonitoring support (telemetric group) or to a group without contact to our clinic (control group). At baseline, and after six and twelve months, body weight, body composition (bioelectrical impedance analysis), and parameters of the metabolic syndrome were assessed at our clinic.

RESULTS

16 participants terminated the study prematurely during the first 6 months and 19 participants (10 from the telemetric group and 9 from the control group) during the second 6 months. According to the intention-to-treat principle, mean weight loss was 6.7 kg (p < 0,001), mean loss of body fat was 5.1 kg (p < 0,001), and mean loss of fat-free mass was 1.6 kg (p < 0,001) within the first six months. Moreover, metabolic and cardiovascular risk markers such as waist circumference, blood pressure, serum triglycerides and blood glucose declined significantly (p < 0,001). Prevalence of the metabolic syndrome fell from 49.5% to 42.0 % (p < 0,05). During the second six months body fat content, waist circumference, and blood glucose increased again in the control group but not in the telemetric group (p < 0,05-0,001).

CONCLUSION

The telemetrically-guided weight loss program was a more efficacious measure than the less intensive support without telemonitoring.

Plasma biomarkers of myocardial fibrosis and remodeling in terminal heart failure patients supported by mechanical circulatory support devices

BACKGROUND

In this study we analyzed putative biomarkers for myocardial remodeling in plasma from 55 endstage heart failure patients with the need for mechanical circulatory support (MCS). We compared our data to 40 healthy controls and examined if MCS by either ventricular assist devices or total artificial hearts has an impact on plasma concentrations of remodeling biomarkers.

METHODS & RESULTS

Plasma biomarkers were analysed pre and 30 days post implantation of a MCS device using commercially available enzyme linked immunosorbent assays (ELISA). We observed that the plasma concentrations of remodeling biomarkers: tissue inhibitor of metalloproteinase 1 (TIMP1), tenascin C (TNC), galectin 3 (LGALS3), osteopontin (OPN) and of neurohumoral biomarker brain natriuretic peptide (BNP), are significantly elevated in patients with terminal heart failure compared to healthy controls. We did not find elevated plasma concentrations for matrix metalloproteinase 2 (MMP2) and procollagen I C-terminal peptide (PCIP). However, only BNP plasma levels were reduced by MCS, whereas the concentrations of remodeling biomarkers remained elevated or even increased further 30 days after MCS. LGALS3 plasma concentrations at device implantation were significantly higher in patients who did not survive MCS due to multi organ failure (MOF).

CONCLUSIONS

Our findings indicate that mechanical unloading in endstage heart failure is not reflected by a rapid reduction of remodeling plasma biomarkers.

Long-term patency of cephalic vein in coronary bypass surgery

In the situation where the saphenous veins were unavailable, cephalic vein was the second choice in the beginning of 1980s. The routine use of saphenous vein and recent enthusiasm for arterial surgical myocardial revascularization lead to less attention on this conduit. We reported a patient undergoing redo coronary bypass surgery after 18 years of having cephalic vein grafts.

Impact of recipient's age on heart transplantation outcome

BACKGROUND

The shortage of donor hearts stimulates the debate whether heart transplantation is justified for older recipients. We studied the effect of recipient's age on heart transplantation outcome in a large cohort of recipients.

METHODS

Between March 1989 and December 2004, 1262 adult recipients underwent heart transplantation. Recipients were divided into two groups: 540 recipients aged younger than 55 years and 722 aged 55 years or older.

RESULTS

The overall 30-day mortality risk was 9%, at 6% for recipients younger than 55, and 10% for recipients 55 years or older (p = 0.005). Rejection, multiorgan failure, infection, and right heart failure dominated the causes of early death in both groups. The 1-, 5-, 10-, and 15-year survival was 84%, 75%, 60%, and 50%, respectively, for recipients younger than 55 years, and 73%, 63%, 48%, and 35%, respectively, for recipients aged 55 years and older (p < 0.001). The mortality rate for those who survived the first month was 58/1000 patient-years. The main causes for late mortality were cardiac allograft vasculopathy, rejection, and infection for recipients younger than 55 years; and infection, malignancies, and rejection for recipients aged 55 years or older. Both the crude and adjusted hazard ratio increased with increasing recipient's age.

CONCLUSIONS

The outcome of heart transplantation in older recipients is less favorable than in younger recipients. The decision to offer heart transplantation to recipients older than 55 years should be considered cautiously.

Survival analysis in heart transplantation: results from an analysis of 1290 cases in a single center

BACKGROUND

The clinical profiles of recipients and donors eligible for the procedure as well as the procedure itself have changed over time. We determined the impact of changes in baseline risk profiles at different transplant periods on outcome, and the time-specific distribution of causes of death.

PATIENTS AND METHODS

Adult heart transplantations were performed consecutively on 1290 patients. Three transplant periods were defined: 1989-1993, 1994-1998, and 1999-2004.

RESULTS

Recipient age and body mass index, previous cardiac surgery, high urgency status, need of ventricular assist device, waiting time (to transplantation and on ventricular assist device), donor age and body mass index, donor-recipient body mass index mismatch, and ischemic and cardiopulmonary bypass time were significantly different over the three transplant periods. There was, however, no significant difference in mortality risk. The major causes of deaths were: acute rejection, multiorgan failure, and right heart failure (<or=30 days); infection and acute rejection (31 days to 1 year); malignancy, acute rejection, and cardiac allograft vasculopathy (>1-5 years); cardiac allograft vasculopathy and malignancy (>5-10 years); and malignancy and infection (>10 years). The overall 1-, 5-, 10- and 15-year survival was respectively 77%, 67%, 53% and 42%. There was no difference in survival by different transplant periods (p=0.68).

CONCLUSION

Despite clearly increased baseline risk profiles over time, the outcome of adult heart transplantation remains stable and encouraging. Cardiac allograft vasculopathy, malignancy, and infection threaten the long-term survival.