Detection of valve malfunction after mechanical MVR using digital phonocardiography.

We present the case of a 63-year-old female patient who developed severe chronic dyspnea two years after mechanical mitral valve replacement (MVR). Conventional cardiac diagnostics including echocardiography, fluoroscopy, right and left heart catheterization could not detect any malfunction. Only digital phonocardiography was able to show alterations of the typical acoustic signal. Based on the symptoms, the clinical history and these abnormal findings the decision was taken to reoperate. Intraoperatively, a ruptured tendinous chord was found, impeding the inferior leaflet. Redo MVR was performed.

Patient-prosthesis mismatch and left ventricular remodelling after implantation of Shelhigh SuperStentless aortic valve prostheses.

AIM: Aortic valve replacement is a standard procedure for the treatment of severe aortic valve stenosis. Due to lower flow velocities stentless valves are associated with a more effective regression of left ventricular hypertrophy in comparison to stented valves. However, mismatch between body surface area and valve size supports unfavourable hemodynamic results. The aim of the study was to analyze hemodynamic parameters by echocardiography after implantation of the Shelhigh SuperStentless bioprosthesis and to analyze the occurrence of patient-prosthesis mismatch and left ventricular remodelling in this specific valve type. METHODS: A total of 20 patients with severe aortic stenosis underwent implantation of a Shelhigh Super Stentless prosthesis. Clinical and echocardiographic assessment was done prior to, immediate after and six months after surgery. RESULTS: All surgical procedures were successful, no surgery-related complication was documented perioperatively. One patient died after development of multiorgan failure. Echocardiography during the first eight days after surgery showed mean gradients of 16 mmHg, mean valve orifice areas of 1.8 cm(2) and indexed effective orifice areas at 0.95 cm(2)/m(2). Six-months follow-up data were obtained in 19/20 patients. There were no relevant changes in echocardiographic hemodynamic findings at the time of follow-up measurements. Significant regression of left ventricular hypertrophy was shown (P=0.0088). A patient-prosthesis mismatch occurred in one patient (0.54 cm(2)/m(2)). No recurrent symptoms were documented. CONCLUSION: Patient-prosthesis mismatch after implantation of SuperStentless Shelhigh prosthesis is rare. A significant regression of left ventricular hypertrophy could be shown after six months. Hemodynamic valve function assessed by echocardiography may be predicted early after surgery.

Aortic valve replacement after previous coronary artery bypass grafting: experience with a simplified approach.

AIM: Aortic valve replacement (AVR) after previous coronary artery bypass grafting (CABG), particularly in a patent left internal thoracic artery (ITA), is a challenge. Avoidance of injuring the patent graft and ensuring myocardial protection are important issues in the management of these patients. The aim of this study was to evaluate a simplified surgical approach to these reoperations. METHODS: Between January 2003 and June 2005, 19 of 287 AVRs performed at our institution were in a patient subset (mean age 70 years, range: 62-82) who received AVR after previous CABG surgery. The aortic valve gradients were between 50 and 107 mm Hg. Our operation strategy followed the KIS-principle (keep it simple): both femoral vessels were cannulated using the Seldinger technique. Only the area around the ascending aorta and the right atrium was dissected to permit x-clamping, aortotomy, and catheterization for retrograde cardioplegia and a left ventricular vent. The anterior aspect of the heart and the left side, where the ITA was embedded and patent, were left untouched and not clamped. RESULTS: The mean interval between the first and second operation was 6.5 years. Fourteen patients received biological prostheses. Four patients received an additional surgery at the time of AVR. The mean operating time was 267 min; the mean AoX-clamp time was 63 min. One patient died because of severe heart failure. In all others the postoperative course was uneventful. CONCLUSIONS: We believe that the indication for AVR in patients scheduled for CABG should be re-evaluated. In those in which Redo-surgery for new or increased valve stenosis is indicated, a simple and safe surgical option is presented.

Demographic and perioperative factors associated with initial and prolonged sinus node dysfunction after orthotopic heart transplantation. The impact of ischemic time.

The etiology of sinus node (SN) dysfunction after orthotopic heart transplantation as assessed by the origin of rhythm, heart rate (HR), and, provided the origin of rhythm was sinus, by corrected sinus node recovery time (CSNRT) was studied in 50 patients. The possible influences on postoperative donor SN function of donor age, recipient age, underlying pretransplant heart disease, pretransplant amiodarone (AMIO) treatment, date of surgery, ischemic time, surgical technique of atrial incision, the use of different cardioplegic solutions during the study period, and rejection were evaluated. The results thus obtained indicate that SN dysfunction is common after cardiac transplantation and pinpoint to a different etiology of transient (restoration of normal SN function within 4 postoperative weeks) and persistent (SN function still impaired at 3 months) SN dysfunction. Of the several demographic and perioperative variables evaluated, only ischemic time had an influence on postoperative SN function in that ischemic times were significantly longer in patients with impaired SN function when compared with patients exhibiting normal SN function (148 +/- 39 min vs. 110.5 +/- 36 min, respectively, P = 0.001). Further stratification according to the duration of SN dysfunction revealed significantly longer ischemic times in patients with transiently impaired SN function only (156.3 +/- 35 min vs. 110.5 +/- 36 min, P = 0.0026). No relation to persistent SN dysfunction of ischemic time (130.5 +/- 36 min vs. 110.5 +/- 36 min, P = ns) or any other factor investigated was found.

The progression of mild acute cardiac rejection evaluated by risk factor analysis. The impact of maintenance steroids and serum creatinine.

The natural course of mild acute cardiac allograft rejection (MAR) under cyclosporine-based therapy is generally considered benign, and usually antirejection therapy is not instituted. The present study was undertaken to determine the frequency of and the risk factors for progression of MAR into a clinically significant (moderate or severe) rejection on subsequent endomyocardial biopsy (EMB). Among 167 cardiac recipients, transplanted from 3/1984 to 4/1990, MAR under cyclosporine-based therapy was diagnosed on 220 EMBs. Depending upon the outcome on the subsequent EMB, MAR was categorized as progressive or nonprogressive. This served as the dependent variable for a stepwise logistic regression analysis evaluating 11 covariates as potential risk factors: perioperative antibody prophylaxis (ATG vs. OKT3), maintenance therapy, underlying disease, HLA-mismatches for A- and B + DR-loci, serum creatinine (mg/dl) and cyclosporine HPLC blood level (ng/ml) at diagnosis of MAR and at subsequent biopsy, recipient age, donor age. 40 (18.2%) of 220 MARs became progressive as opposed to 37 (7.3%) of a control cohort of 507 negative EMBs (P less than 0.0001). Stepwise logistic regression yielded the type of maintenance therapy (P = 0.0019) and serum creatinine level at diagnosis of MAR (P = 0.0615) as independent predictors of progression of MAR. After adjustment for influence of maintenance therapy and serum creatinine none of the cyclosporine variables provided any additional information. MARs without maintenance steroids and low serum creatinine levels had the highest risk (37.2% observed incidence) to develop moderate or severe rejection on subsequent EMB. This analysis supports evidence that diagnosis of MAR on EMB is associated with a considerable high progression rate into clinically significant rejection when compared to negative EMBs. Progression particularly occurs in MAR under steroid-free maintenance therapy and suggests early augmentation of immunosuppression. In terms of progression of MAR serum creatinine values, obviously indicating cyclosporine nephrotoxicity, appear to reflect the extent of cyclosporine-mediated immunosuppressive activity more properly than parameters of its bioavailability by measuring cyclosporine HPLC blood levels.

Clinical and electrophysiologic correlates of sinus node dysfunction after orthotopic heart transplantation. Observations in 42 patients.

We assessed incidence and course of postoperative SN dysfunction in 42 cardiac transplant recipients. RHY, HR and CSNRT were compared in distinguishing between persistent (9 of 42 patients) and transient (11 of 42) SN dysfunction. Persistent SN dysfunction was distinguished by a significantly lower HR (day 14: 46.2 +/- 12 vs 67 +/- 19 bpm; day 21: 40.3 +/- 21 vs 70.8 +/- 16 bpm; p less than 0.05, respectively) and by RHY: postoperative AS (3 of 42) was found only in patients whose SN dysfunction persisted while patients with SR but prolonged CSNRT more often had transient impairment (6 of 42 vs 2 of 42); CSNRT, in contrast, is unlikely to be useful in distinguishing between transient and persistent SN dysfunction since exceptionally long CSNRTs (11,340 ms. 12,080 ms) occurred in patients with both types. Ischemic times were significantly longer in patients with transient impairment when compared with the group with normal SN function (155.1 +/- 36 vs 109.2 +/- 36 min, p less than 0.05) but did not differ significantly in patients with persistent SN dysfunction (124.8 +/- 32 min). Thus, (1) SN dysfunction after cardiac transplantation is common but most often transient; (2) RHY and HR are adequate follow-up parameters and best predictors of long-term SN function; (3) SN dysfunction after transplantation has important clinical implications given the unreliability of lower pacemakers to take over in 3 patients; (4) transient SN dysfunction is related to duration of ischemia during hypothermic preservation whereas pathogenesis of persistent SN dysfunction remains to be elucidated.

Postoperative sinus node dysfunction in the transplanted heart. Impaired automaticity but normal refractoriness.

We describe the use of the extrastimulus technique to define the range of sinus node (SN) effective refractoriness (SNERP) in the denervated transplanted human heart. SNERP could be successfully determined in 18 of 28 patients corresponding to 25 of 43 SN studies and ranged from 210 to 360 ms at a basic pacing cycle length of 500 ms (95 percent confidence limits: 252.5 to 296.2 ms), which is shorter than reported in the innervated native heart. Sixteen data sets in 12 patients showed normal SN function and nine sets of measurements in seven patients showed abnormal SN function (corrected SN recovery time greater than 520 ms). While recovery time was profoundly abnormal (279.7 +/- 94 vs 7,284.8 +/- 10,454, p less than 0.001), the SNERP did not differ significantly between the groups (274.3 +/- 40 vs 286 +/- 42 ms at 500 ms, p = 0.5) and was normal at a range of 220 to 340 ms even in those patients with grossly impaired SN recovery (SNERP in patients with normal SN function: 210 to 360 ms at 500 ms). This study demonstrates that SN refractoriness in the transplanted human heart is shorter than previously reported in innervated controls and suggests that posttransplantation SN dysfunction is characterized by impaired automaticity rather than impaired refractoriness.

Monitoring of mononuclear cell subsets isolated from the coronary sinus and the right atrium in patients after heart allograft transplantation.

The rejection of a transplanted heart leads to an accumulation of mononuclear cells in the cardiac tissue and to reactions of the antigen-recognizing cells with the foreign tissue. Consequently, during rejections immunologic changes, such as the number of mononuclear cells and the patterns of mononuclear cell subpopulations, should be detectable by analysis of mononuclear cells from the coronary sinus of transplanted hearts. Seventy-nine endomyocardial biopsies were performed in 37 patients. Severity of graft rejection was classified by the Billingham scheme. Thirty-two biopsy specimens showed no rejection, 33 mild, and 14 moderate rejection. After endomyocardial biopsy the coronary sinus was catheterized under x-ray guidance. Heparinized blood samples were obtained from the coronary sinus and the right atrium, and mononuclear cell counts and subpopulation pattern were compared. Patients without rejection and patients with mild rejection showed no significant differences in the patterns of mononuclear cell subpopulation identified in right atrium blood. However, a significant (1.56-fold) increase of mononuclear cells was assessed in the CS blood (p less than 0.01). Moderate rejections showed a 4.2-fold augmentation of mononuclear cells in the coronary sinus (p less than 0.005) compared with nonrejections. In addition, the T-helper/inducer (CD4) percentage increased from 27.1% in the right atrium to 41.2% in the coronary sinus (p less than 0.005), natural killer cells (CD16) from 17.7% to 31.8% (p less than 0.005), and the interleukin 2 receptor-bearing cells from 6.6% to 15.3% (p less than 0.005). Percentage of pan-T cells (CD3), T-cytotoxic/suppressor cells (CD8), and monocytes (CD14) showed no statistically significant changes. These findings correlated with grading according to endomyocardial biopsy. Using the ratio of values obtained from cells of the coronary sinus and the right atrium rendered the coronary sinus immunologic monitoring independent of changes in the administered immunosuppressive regimen. The specificity of the described method was as good as that of endomyocardial biopsy. It is concluded that the discrimination of the patterns of mononuclear cell subpopulations from right atrium versus coronary sinus blood samples is highly sensitive and allows the correct diagnosis of graft rejection within 1 to 2 hours.

The determinants of elevated total plasma cholesterol levels in cardiac transplant recipients administered low dose cyclosporine for immunosuppression.

Elevated total plasma cholesterol level is a frequent finding after cardiac transplantation. To identify risk factors for the development of hypercholesterolemic states, we applied multivariate statistics in a logistic and linear manner. Six-month posttransplantation levels of total plasma cholesterol in 57 adult heart recipients were available for analysis. Maintenance immunosuppression was carried out with either cyclosporine and azathioprine or both agents plus low-dose steroids. Total plasma cholesterol levels were dichotomized for the logistic analysis (1) by the age- and sex-matched 75th and 90th percentiles of a reference population according to National Institutes of Health treatment guidelines and (2) by the cut point 250 mg/dl. Twelve potential risk factors were evaluated as covariates: recipient age, body weight after 6 months, body weight gain over 6 months, body mass index after 6 months, body mass index gain over 6 months, current cyclosporine dosage, trough level of cyclosporine in whole blood according to high-performance liquid chromatography after 6 months, cumulative cyclosporine dosage over 6 months, serum bilirubin, type of original cardiac disease, maintenance steroids, and steroid bolus treatment. Multivariate logistic regression yielded the type of original cardiac disease as a significant predictor of posttransplantation hypercholesterolemia exceeding the 90th percentile (p = 0.019) and of hypercholesterolemia exceeding 250 mg/dl (p = 0.032). Maintenance steroids were identified as a second significant cofactor (p = 0.069) for total plasma cholesterol levels exceeding 250 mg/dl. Multiple linear regression again revealed the type of original cardiac disease and maintenance steroids as significant predictors by p values of 0.005 and 0.013, respectively. Patients with coronary artery disease as the original cardiac pathology and low-dose maintenance steroids had the greatest risk for the development of elevated total plasma cholesterol levels after cardiac transplantation. However, the overall predictive quality of the linear model was limited (multiple r value 0.43), which indicates that other variables besides the tested ones attributed to elevated total plasma cholesterol levels. These results confirm the adverse role of maintenance steroids on posttransplantation hypercholesterolemia and demonstrate the type of original cardiac disease as the most important risk factor. They suggest that abnormalities of lipoprotein metabolism and dietary factors continue to affect total plasma cholesterol levels after cardiac transplantation.

Independent risk factors predicting acute graft rejection in cardiac transplant recipients treated by triple drug immunosuppression.

To assess independent risk factors predicting the occurrence of clinically significant acute rejection episodes in the first 6 months after cardiac transplantation, we performed a multivariate stepwise logistic regression analysis. Forty-three recipients, undergoing transplantation between September 1986 and May 1988, were eligible for analysis and received standardized, low-dose triple drug maintenance immunosuppression with cyclosporine, azathioprine, and prednisolone. Immunoprophylaxis was supplemented perioperatively with either a polyclonal (antithymocyte globulin, N = 26) or a monoclonal (OKT3, N = 17) anti-T-cell antibody. Investigated, conceivable risk factors comprised recipient and donor age, ischemic time, perioperative anti-T-cell antibody prophylaxis, recipient preoperative status, underlying disease, previous cardiac operation, and histocompatibility parameter (mismatches for HLA-A, HLA-B, HLA-DR, HLA-B+DR, HLA-A+B+DR, and Rh0[D] antigen, HLA-DRw6 positive recipient, and identify for ABO system). Univariate analysis suggested significant influence of the type of antibody used perioperatively (p = 0.0024) and the number of mismatches for HLA-A+B+DR (p = 0.0037) and for HLA-B+DR (p = 0.0043). Stepwise logistic regression yielded the number of mismatches for HLA-B+DR (p = 0.0029) and the type of antibody used perioperatively (p = 0.0031) as being highly significant predictors of acute cardiac rejection. Six-month freedom from rejection was 100%, 41%, and 27% for recipients with two, three, and four mismatches for HLA-B+DR and 59% versus 22% for recipients with polyclonal versus monoclonal antibody prophylaxis. Similar to results with kidney transplantation, these results indicate that a poor donor/recipient match for combined HLA-B+DR loci constitutes an independent risk factor for acute graft rejection in low-dose triple drug immunosuppressed cardiac recipients, which stimulates the potential concept of prospective HLA matching. In our experience OKT3 prophylaxis provides significantly less effective prevention of acute rejection than a comparable course of antithymocyte globulin.

Quality of life after orthotopic heart transplantation.

During the last decade heart transplantation has become the chosen method to treat terminally ill patients suffering from severe cardiac illness. It was the aim of our study to retrospectively survey life quality of donor organ recipients who underwent heart transplantation during the first years of transplantation at our center (1984 through 1987). Thirty-five patients were asked to evaluate their postoperative improvement or deterioration and their satisfaction with the level reached on visual scales. Life quality was defined in nine areas: physical, emotional, mental, vocational, and sexual status, financial situation, leisure activities, partnership, and overall life quality. The following results were obtained: (1) our former patients informed us about a distinct improvement in almost all dimensions (except financial situation). We found an absolute increase in life quality after heart transplantation. (2) Although improvement was ranked best for physical status, there was also a high amelioration in psychosocial fields. (3) A significant difference was seen between changes in condition and satisfaction in the financial situation (z = 2.3) and in partnership (z = 2.9), in which the latter was ranked higher. (4) The date of transplantation (less/more than 2 years ago) had no influence on the evaluation of postoperative life quality.

Domino transplantation of heart-lung and heart: an approach to overcome the scarcity of donor organs.

The scarcity of donor organs remains the main restricting factor for heart, heart-lung, and lung transplantation. Recently new techniques for separate harvesting of the heart and the lungs from one donor for two recipients have been developed. These techniques enable the optimal use of available grafts. Another approach to this problem is combined heart-lung transplantation for patients with end-stage lung disease but still adequate heart performance, and the subsequent transplantation of the recipient's heart into a second patient with end-stage heart disease. The main advantages of this procedure are its technical simplicity compared with double lung transplantation; the preservation of aortobronchial collaterals, resulting in improved blood supply to the trachea; and the possibility of transplanting a conditioned right heart well adapted to chronically elevated pulmonary pressure. We recently have performed this procedure with good clinical results and suggest it as the method of choice whenever two well-matched recipients are available.

Inducible atrial flutter and fibrillation after orthotopic heart transplantation.

Inducible atrial flutter (two patients) and fibrillation (two patients) were observed in a series of 35 heart transplant patients who underwent evaluation of sinus node function including premature atrial stimulation. The sinus node function was entirely normal in both patients with inducible atrial flutter. In contrast it was profoundly abnormal in the patients with inducible atrial fibrillation. Atrial fibrillation was no longer inducible as the sinus node function became borderline normal. These observations suggest extensive electrical atrial abnormality, including the sinus node, in patients with atrial fibrillation, and temporary pacing should be available when considering cardioversion in patients with atrial fibrillation early after heart transplantation. Atrial flutter, in contrast, may be inducible in the absence of any sinus node abnormality and without any evidence of rejection.

Decreasing use of donated blood and reduction of bleeding after orthotopic heart transplantation by use of aprotinin.

Twenty patients undergoing orthotopic heart transplantation were randomized preoperatively to receive either the serine proteinase inhibitor aprotinin in a low dose (560 mg; n = 10) or a placebo (control group, n = 10) at the time of transplantation. Blood loss 24 and 48 hours after transplantation was significantly lower in the group treated with aprotinin (i.e., 510 ml vs 820 ml, p less than 0.01, and 690 ml vs 1000 ml, p less than 0.03, respectively. Accordingly, the aprotinin group required significantly less transfused blood in the first 48 postoperative hours 0 to 250 ml versus 0 to 1000 ml (p less than 0.04). Seventy percent of the patients treated with aprotinin underwent transplantation without the need of nonautologous blood, compared with only 30% in the control group.

Saline-irrigated, cooled-tip radiofrequency ablation is an effective technique to perform the maze procedure.

BACKGROUND: We evaluated the effectiveness of the saline-irrigated-cooled-tip-radiofrequency ablation (SICTRA) to produce linear intraatrial lesions. METHODS: Thirty patients with chronic atrial fibrillation and mitral valve disease were consecutively randomized to have mitral valve operation either with a Maze procedure (group A) or without (group B). Intraatrial linear lesions were made with an SICTRA catheter (20 to 32 W; 200 to 320 mL/h saline). An echocardiography and 24-hour electrocardiogram were obtained 12 months postoperatively. RESULTS: The cumulative frequencies of sinus rhythm in group A and B were 0.80 and 0.27 (p < 0.01). Restored biatrial contraction was present in 66.7% (6 of 9) of the group A patients in sinus rhythm. One patient from each group received a permanent pacemaker because of bradycardia. A fatal renal bleeding and mediastinitis occurred in 2 group A patients, 6 weeks postoperatively. One group A patient had sudden cardiac death at home, 4 months after operation. One patient from each group had lethal respiratory failure, 7 and 10 months after operation. Survival after 12 months for group A and B was 73% and 93% (p = 0.131). CONCLUSIONS: The SICTRA appeared to be an effective technique to perform the Maze procedure.

Incidence and severity of acute cardiac allograft rejection with two different low-dose cyclosporine maintenance protocols.

Currently cyclosporine (CyA) represents the main immunosuppressive agent used after cardiac transplantation and usually is administered in combination with prednisone and/or azathioprine for prevention of graft rejection. From March, 1984, to August, 1987, 53 patients underwent orthotopic heart transplantation for terminal-stage heart disease at the Second Department of Surgery, University of Vienna. All patients received CyA in increasing dosage (3 mg/kg to 6-10 mg/kg) postoperatively according to renal function, obtaining a trough high-pressure liquid chromatographic whole-blood target level of 200 to 400 ng/ml at the end of the first week. CyA was subsequently tapered to 100 to 150 ng/ml after 6 months. From March, 1984, through April, 1986, maintenance immunosuppression was carried out with a double-drug regimen of CyA and azathioprine. Since May, 1986, a triple-drug schedule was applied with CyA, azathioprine, and prednisone. Under triple-drug therapy, the incidence of mild, moderate (p less than 0.0001), and severe (p = 0.05) allograft rejection proven by endomyocardial biopsy decreased significantly with a corresponding increase of absent (p less than 0.0001) rejection. Freedom from moderate, severe, and lethal graft rejection, number of rejection episodes per patient after 1 year (double drug, 1.0, versus triple drug, 2.5), and patient survival disclosed significant improvement for recipients of the triple-drug regimen. Both groups had the same incidence of infectious complications; freedom from death by infection after 1 year was 90% versus 91% (double versus triple drug, p = 0.20).(ABSTRACT TRUNCATED AT 250 WORDS)

Prophylactic use of hyperimmunoglobulin for cytomegalovirus infection in heart transplantation.

Cytomegalovirus (CMV) infection in solid organ recipients can endanger the immunosuppressed patient and increase vulnerability to secondary infections and the high risk of rejection triggered by the viral disease. The effect of passive immunization against CMV was examined in 69 heart transplant patients. The patients received weekly administrations of 1 ml/kg of CMV hyperimmunoglobulin from the day of transplantation until the 30th postoperative day. Forty-four of the patients were monitored clinically and serologically up to the 120th postoperative day. Nine patients showed clinical and serologic signs of CMV infection; in 15 the only evidence of CMV infection was a rise in antibody titers. The remaining 20 patients showed no clinical or serologic signs of CMV infection. Three patients who were seronegative preoperatively remained seronegative until the end of the observation period. The results indicate a potential therapeutic benefit of hyperimmunoglobulin prophylaxis to prevent infectious complications due to CMV in heart transplant patients.

Relationship between position of the coronary sinus catheter and distribution of cardioplegia.

BACKGROUND AND AIMS OF THE STUDY: The use of retrograde cardioplegia is controversial, mainly due to differences in theoretic and methodologic aspects. The aim of this study was to identify an optimal position for the cardioplegia catheter within the coronary sinus. METHODS: Thirteen cadaver hearts was used, and three different catheter positions in the coronary sinus were compared, using a radio-opaque dye which had a viscosity similar to that of blood. The distribution of dye at different segments of the heart was examined. RESULTS: Dye distribution, indicative of cardiac perfusion, was found to be related to the position of the catheter in the coronary sinus and the quantity of dye injected. CONCLUSIONS: This study demonstrated the efficiency of retrograde cardioplegia, and also that optimal positioning of the catheter and the use of high-volume cardioplegia are required concomitantly for successful perfusion.

Aortic valve replacement: better myocardial protection by cold or warm retrograde blood cardioplegia?

BACKGROUND AND AIMS OF THE STUDY: To determine whether warm blood cardioplegia (BCP) is superior to cold BCP in terms of myocardial protection, we compared warm (37 degrees C) and cold (4 degrees C) continuous retrograde administration of BCP in 40 patients undergoing aortic valve replacement (AVR) in a prospective, randomized study. MATERIALS AND METHODS: The main subjects of investigation were the myocardial oxygen consumption and the maintenance of the ultrastructure of the tissue. In addition, we looked at intraoperative recordings of time, heart rhythm disturbances, CK/MB serum levels, and inotropic support. RESULTS: We found, that oxygen consumption is significantly higher during warm BCP (7.95-10.38 ml/min) than during cold BCP (2.11-3.47 ml/min). Mild, reversible myocardial damage occurs during cold and warm BCP. The intraoperative serum potassium level was significantly higher after warm (7.25 mmol/l) than after cold (6.55 mmol/l) BCP. There was no statistically significant difference in the duration of extracorporeal circulation and of cardiac arrest, the CK/MB serum level or the recorded right and left ventricular performance data in the two groups. CONCLUSIONS: We conclude that continuous retrograde warm BCP is not superior to continuous retrograde cold BCP as far as myocardial protection is concerned. The administration of cold BCP prolongs the tolerated ischemic time of the myocardium and provides a higher safety margin.

Examination of hemolytic potential with the On-X(R) prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: Mechanical valves are known to produce chronic, subclinical hemolysis in most patients. Generally, haptoglobin is reduced to below normal in most patients, while lactate dehydrogenase (LDH) is increased to as much as 200% above the upper normal, sometimes resulting in anemia. The study was designed to investigate the clinical hemolysis of the On-X(R) prosthetic heart valve in a multicenter experience with a standard protocol and a single clinical laboratory. METHODS: Between September 1996 and August 1998, 248 patients underwent isolated valve replacement at 10 European centers. Blood samples were collected from these preoperatively and at 3-6 months and one year postoperatively. All samples were analyzed at a central laboratory, thus assuring poolability of the data. In total, 151 patients were tested at 3-6 months, and 62 at one year. Blood parameters measured were LDH, haptoglobin, hematocrit, total hemoglobin, red cell count and reticulocyte count. Paired analysis was used to compare preoperative baseline values with 3-6-month and one-year values. Data were analyzed with regard to both valve position and size. RESULTS: At 3-6 months and one year after surgery, average values for hematocrit, hemoglobin, red cell count and reticulocyte count were all near the center of the normal range, regardless of valve position or size. Statistically significant increases in red cell count and decreases in reticulocyte count occurred after both aortic valve replacement (AVR) and mitral valve replacement (MVR). These changes were of no clinical importance, but indicate that anemia has not occurred in these patients. At 3-6 months, haptoglobin was reduced to below normal in 86% of both AVR and MVR patients; this also occurred after one year and was statistically significant. Postoperatively, the mean LDH value in AVR was 228 U/l (91% of upper normal, 250 U/l) at 3-6 months, and 246 U/l (98% of upper normal) at one year. In MVR, these LDH values were 271 U/l (108% of upper normal) and 265 U/l (106% of upper normal). CONCLUSIONS: These results indicate that the On-X valve causes lower levels of chronic hemolysis in the immediate postoperative period and up to one year after surgery, especially when compared with reports of LDH elevations up to 200% of upper normal. Hemolytic anemia has not occurred in this patient population.