Is early anticoagulation with warfarin necessary after bioprosthetic aortic valve replacement?

OBJECTIVES

Freedom from anticoagulation is the principal advantage of bioprosthesis; however, the American Heart Association/American College of Cardiology and the American College of Chest Physicians guidelines recommend early anticoagulation with heparin, followed by warfarin for 3 months after bioprosthetic aortic valve replacement. We examined neurologic events within 90 days of bioprosthetic aortic valve replacement at our institution.

METHODS

Between 1993 and 2000, 1151 patients underwent bioprosthetic aortic valve replacement with (641) or without (510) associated coronary artery bypass. By surgeon preference, 624 had early postoperative anticoagulation (AC+) and 527 did not (AC-). In the AC- group, 410 patients (78%) received antiplatelet therapy. Groups were similar with respect to gender (female, 36% AC+ vs 40% AC-, P = .21), hypertension (64% AC+ vs 61%, P = .27), and prior stroke (7.6% AC+ vs 8.5% AC-, P = .54). The AC+ group was slightly younger than the AC- group (median, 76 years vs 78 years, P = .006).

RESULTS

Operative mortality was 4.1% with 43 (3.7%) cerebrovascular events within 90 days. Excluding 18 deficits apparent upon emergence from anesthesia, we found that postoperative cerebrovascular accident occurred in 2.4% of AC+ and 1.9% AC- patients. By multivariable analysis, the only predictor of operative mortality was hypertension ( P < .0001). Postoperative cerebrovascular accident was unrelated to warfarin use ( P = .32). The incidence of mediastinal bleeding requiring reexploration was similar (5.0% vs 7.4%), as were other bleeding complications in the first 90 days (1.1% vs 0.8%). No variables were predictive of bleeding by multivariate analysis.

CONCLUSIONS

Although these data do not address the role of antiplatelet agents, early anticoagulation with warfarin after bioprosthetic aortic valve replacement did not appear to protect against neurologic events.

Low pressure giant pulmonary artery aneurysms in the adult: natural history and management strategies

OBJECTIVE

To describe aspects of the natural history and pathophysiology of giant low pressure pulmonary artery aneurysms and to propose potential surgical strategies.

DESIGN

Cross sectional retrospective review.

SETTING

Supraregional tertiary referral centre.

PATIENTS

All adult patients referred for assessment of giant pulmonary artery aneurysm retrospectively identified from the Mayo Adult Congenital Heart Disease Clinic database.

METHODS

Patient data were reviewed from hospital records, including echocardiograms, magnetic resonance images, radiographs, and histology slides.

RESULTS

Four patients were identified with a median age of 52 years (range 37-64 years). Presenting symptoms were effort related dyspnoea, chest discomfort, and hoarseness in one patient. All patients had pulmonary regurgitation and clinical evidence of right ventricular enlargement in association with a pulsatile mass at the upper left sternal edge. Transthoracic echocardiography showed the giant pulmonary artery aneurysm involving the main pulmonary artery and proximal branches, and confirmed severe pulmonary regurgitation in all patients. None of the patients had intimal tearing, medial dissection, or pulmonary arterial rupture. The pulmonary valve was replaced to relieve symptoms and preserve right ventricular function. Pulmonary arterial histology showed medial degeneration of elastic fibres with accumulation of basophilic ground substance.

CONCLUSIONS

Rupture or dissection of these low pressure aneurysms is rare. The timing of surgical intervention should be determined by changes in right ventricular size and function resulting from pulmonary regurgitation or pulmonary stenosis, and not the size of the aneurysm.

Late results of the Rastelli operation for transposition of the great arteries

The Rastelli operation, first performed in 1968, was developed for repair of transposition of the great arteries with associated ventricular septal defect and severe pulmonary stenosis. This operation includes placement of an intracardiac baffle to direct left ventricular blood to the aorta and an extracardiac valved conduit to establish continuity between the right ventricle and the pulmonary arteries. Over the last 3 decades, the Rastelli operation has been performed with a progressive decline in early mortality, and it remains the preferred repair for transposition, ventricular septal defect, and severe fixed valvular or subvalvular pulmonary stenosis. This chapter examines the late results of our 33-year experience with the Rastelli operation and describes our operative technique.

Risk factors for ischemic optic neuropathy after cardiopulmonary bypass: a matched case/control study

Visual loss (acuity or field) secondary to ischemic optic neuropathy (ION) is a rare but devastating complication of cardiac surgery involving cardiopulmonary bypass (CPB). We determined clinical features and risk factors for ION by a retrospective time-matched, case-control study. ION was identified in 17 (0.06%) patients out of 27,915 patients who underwent CPB between January 1, 1976, and December 31, 1994. For each ION patient, two patients who underwent CPB exactly 2 wk before the ION patient were selected as controls. Data were analyzed by using conditional logistic regression with the 1:2 matched-set feature of 17 cases and 34 controls. Two-tailed P values < or =0.05 were considered significant. From bivariate analysis, smaller minimum postoperative hemoglobin concentration (odds ratio [OR] = 1.9, P = 0.047) and the presence of atherosclerotic vascular disease (OR = 7.0, P = 0.026) were found to be independently associated with ION after CPB, as were smaller minimum postoperative hemoglobin concentration (OR = 2.2, P = 0.027) and preoperative angiogram within 48 h of surgery (OR = 7.2, P = 0.042). In ION patients, 13 (76.5%) of 17 experienced a minimum postoperative hemoglobin value of < 8.5 g/dL, whereas only 14 (41.2%) of 34 control patients experienced values < 8.5 g/dL.

IMPLICATIONS

Patients with clinically significant vascular disease history or preoperative angiogram may be at increased risk for ischemic optic neuropathy after cardiac surgery, especially if the hemoglobin remains low in the postoperative period.

Role of myocardial temperature measurement in monitoring the adequacy of myocardial protection during cardiac surgery

Inadequate myocardial protection continues to be encountered despite improved methods of cardioplegia delivery. Although myocardial temperature is commonly monitored to assess the adequacy of cardioplegia delivery, its relationship to the metabolic status of the myocardium has not been investigated. We prospectively reviewed patients who underwent valvular heart surgery with blood (n = 47) or crystalloid (n = 48) cardioplegia and continuous measurement of intraoperative myocardial tissue pH and temperature. We previously demonstrated a high correlation (r = 0.99) between extracellular myocardial pH, levels of intracellular hydrogen ion concentration, and a lowering of tissue ATP during coronary occlusion. Clinically, optimal metabolic protection was defined as the absence of myocardial tissue acidosis during the period of aortic occlusion as quantified by a temperature-corrected integrated mean pH of 6.8 or greater, which has been shown to be predictive of a favorable postoperative outcome. Age, bypass time, myocardial temperature, myocardial tissue pH at the onset of aortic occlusion, cross-clamp time, and volume of cardioplegia were not significantly different between blood and crystalloid groups. Linear regression analysis demonstrated no significant correlation between mean myocardial tissue pH and the corresponding mean myocardial temperature in either group during aortic occlusion. There was also no correlation between the mean myocardial tissue pH and volume of cardioplegia delivered in both groups. These data demonstrate wide intercardiac and intracardiac variability in the degree of regional tissue acidosis encountered during of hypothermic cardioplegia. Cardioplegia delivery guided by measurement of myocardial temperature or by standardized protocol did not prevent the occurrence of tissue acidosis and thus, did not ensure optimal metabolic protection of the heart. In 95 patients undergoing valvular heart surgery with cold blood or crystalloid cardioplegia, there was no correlation between myocardial tissue pH and mycardial temperature or between myocardial tissue pH and volume of cardioplegia administered. Temperature is a poor indicator of the metabolic state of the myocardium.

Biocompatibility of Trillium Biopassive Surface-coated oxygenator versus uncoated oxygenator during cardiopulmonary bypass

OBJECTIVE

To determine if the Trillium Biopassive Surface (Medtronic Cardiopulmonary, Minneapolis, MN) coating added to the cardiopulmonary bypass oxygenator reduces inflammatory mediators, blood loss, and transfusion requirements.

DESIGN

Prospective, randomized, and blinded human trial.

SETTING

Tertiary care academic medical center.

PARTICIPANTS

Thirty adult patients undergoing elective coronary artery bypass graft surgery.

INTERVENTIONS

Patients received visually identical coated or uncoated oxygenators.

MEASUREMENTS AND MAIN RESULTS

Hemoglobin, hematocrit, leukocyte count, platelet count, terminal complement complex, complement activation, myeloperoxidase, beta-thromboglobulin, prothrombin fragment 1.2, plasmin-antiplasmin, heparin concentration, activated coagulation time, and fibrinogen concentration were measured. Blood loss and blood product usage were recorded. In both groups, there were significant inflammatory alterations with the initiation of cardiopulmonary bypass. In the postprotamine samples, the coated oxygenator group had small but significant increases in hemoglobin, hematocrit, and leukocyte count. There were no differences in inflammatory mediators, blood loss, or transfusion requirements between the coated and uncoated groups.

CONCLUSION

This human trial of Trillium Biopassive Surface-coated oxygenators did not show clinical benefits or clinically important biochemical results.

Posterior pericardial ascending-to-descending aortic bypass: an alternative surgical approach for complex coarctation of the aorta

BACKGROUND

Coarctation of the aorta is commonly associated with recoarctation or additional cardiovascular disorders that require intervention. The best surgical approach in such patients is uncertain. Ascending-to-descending aortic bypass graft via the posterior pericardium (CoA bypass) allows simultaneous intracardiac repair or an alternative approach for the patient with complex coarctation.

METHODS AND RESULTS

Between 1985 and 2000, 18 patients (13 males and 5 females, mean age 43+/-13 years) with coarctation of the aorta underwent CoA bypass through median sternotomy. Before operation, average New York Heart Association class was II (range I to IV), and 15 patients (83%) had systemic hypertension. One or more previous cardiovascular operations had been performed in 12 patients (67%); 10 patients had >/=1 prior coarctation repair. Two patients had prior noncoarctation cardiovascular surgery. Concomitant procedures performed in 14 patients (78%) included the following: aortic valve replacement in 9; coronary artery bypass surgery in 3; mitral valve repair in 2; and septal myectomy, mitral valve replacement, aortoplasty, subaortic stenosis resection, ventricular septal defect closure, and ascending aorta replacement in 1 patient each. All patients survived the operation and were alive with patent CoA bypass at a mean follow-up of 45 months. No graft-related complications occurred, and there were no instances of stroke or paraplegia. Systolic blood pressure fell from 159 mm Hg before surgery to 125 mm Hg after surgery.

CONCLUSIONS

CoA bypass via median sternotomy can be performed with low morbidity and mortality. Although management must be individualized, extra-anatomic CoA bypass via the posterior pericardium is an excellent single-stage approach for patients with complex coarctation or recoarctation and concomitant cardiovascular disorders.

Valvular heart operation in patients with previous mediastinal radiation therapy

BACKGROUND

The outcome of valvular heart operations in patients with previous mediastinal radiation therapy was studied.

METHODS

This is a single center retrospective study of 60 patients (37 females, 23 males) with a mean age of 62 +/- 15 years (28 to 88 years old) operated on from January 1976 to December 1998. Valvular heart operations performed included aortic valve replacements (n = 26), mitral valve procedures (n = 16), tricuspid valve procedures (n = 6), and multiple valve procedures (n = 12). A total of 264 clinical, hemodynamic, electrocardiographic and echocardiographic variables were analyzed.

RESULTS

Total follow-up was 199 patient-years with a mean of 3.3 +/- 3.1 years and a range of 0 to 12.4 years old. Early mortality was 7 patients (12%). Early mortality in patients with constrictive pericarditis was 40% (4 of 10) compared with 6% (3 of 50) in patients without constrictive pericarditis. By univariate analysis, early mortality was associated with constrictive pericarditis (p = 0.011), reduced preoperative ejection fraction (p = 0.015), and longer cardiopulmonary bypass times (p = 0.037). A total of 14 patients (23%) required permanent pacemaker placement before (n = 7), during (n = 1), or early (n = 6) after valvular heart operations. There were 19 late deaths (malignancies, 7; heart failures, 5; other cardiac, 4; and other noncardiac, 3). Overall survival and freedom from late cardiac death and cardiac reoperation at 5 years for hospital survivors were 66% +/- 8%, 82% +/- 7%, and 93% +/- 4%, respectively. By univariate analysis, late cardiac death was associated with low ejection fraction (p = 0.002), New York Heart Association (NYHA) functional class IV (p = 0.004), preoperative congestive heart failure (p = 0.02), and preoperative atrial fibrillation (p = 0.038). Eighty-five percent of the discharged patients were in NYHA functional class I or II at follow-up.

CONCLUSIONS

Early results of valve replacement after mediastinal radiation therapy were good except in the presence of constrictive pericarditis. Long-term outcome was limited by malignancy and heart failure. Early surgical intervention is recommended before the development of risk factors for late death, namely, severe symptoms, left ventricular dysfunction, and atrial fibrillation.

Fatal disseminated aspergillosis following sequential heart and stem cell transplantation for systemic amyloidosis

Infectious complications are a major cause of morbidity and mortality in transplant recipients. We describe a case of fatal disseminated aspergillosis immediately following autologous peripheral stem cell reconstitution in a patient who had undergone orthotopic heart transplantation for systemic amyloidosis. The case described suggests that the infectious risks in patients undergoing these sequential procedures may be distinct from those occurring in patients undergoing either procedure independently. Potential prophylactic and therapeutic interventions are discussed. Since this experimental and evolving approach for the management of systemic amyloidosis is potentially applicable to a limited number of patients, multicenter collaboration may be needed to further define the infectious risks in this unique subset of transplant recipients.

Efficacy of a simple intraoperative transfusion algorithm for nonerythrocyte component utilization after cardiopulmonary bypass

BACKGROUND

Abnormal bleeding after cardiopulmonary bypass (CPB) is a common complication of cardiac surgery, with important health and economic consequences. Coagulation test-based algorithms may reduce transfusion of non-erythrocyte allogeneic blood in patients with abnormal bleeding.

METHODS

The authors performed a randomized prospective trial comparing allogeneic transfusion practices in 92 adult patients with abnormal bleeding after CPB. Patients with abnormal bleeding were randomized to one of two groups: a control group following individual anesthesiologist's transfusion practices and a protocol group using a transfusion algorithm guided by coagulation tests.

RESULTS

Among 836 eligible patients having all types of elective cardiac surgery requiring CPB, 92 patients developed abnormal bleeding after CPB (incidence, 11%). The transfusion algorithm group received less allogeneic fresh frozen plasma in the operating room after CPB (median, 0 units; range, 0-7 units) than the control group (median, 3 units; range, 0-10 units) (P = 0.0002). The median number of platelet units transfused in the operating room after CPB was 4 (range, 0-12) in the algorithm group compared with 6 (range, 0-18) in the control group (P = 0.0001). Intensive care unit (ICU) mediastinal blood loss was significantly less in the algorithm group. Multivariate analysis demonstrated that transfusion algorithm use resulted in reduced ICU blood loss. The control group also had a significantly greater incidence of surgical reoperation of the mediastinum for bleeding (11.8% vs. 0%; P = 0.032).

CONCLUSIONS

Use of a coagulation test-based transfusion algorithm in cardiac surgery patients with abnormal bleeding after CPB reduced non-erythrocyte allogeneic transfusions in the operating room and ICU blood loss.

Late pulmonary valve replacement after repair of tetralogy of Fallot

BACKGROUND

Pulmonary regurgitation appears to be well tolerated early after repair of tetralogy of Fallot; however, it may result in progressive right ventricular dilatation and dysfunction necessitating eventual valve replacement. Our objective was to review our experience with late pulmonary valve replacement after complete repair of tetralogy of Fallot.

METHODS AND RESULTS

A total of 42 patients (16 female and 26 male) were operated on between July 1, 1974, and January 1, 1998. Mean age was 22 years (range 2-65 years). The mean interval between tetralogy repair and pulmonary valve replacement was 10.8 years (range 1.6 months-33 years). Mean follow-up was 7.8 +/- 6.0 years (maximum 23 years). Indications for pulmonary valve replacement included decreased exercise tolerance in 58%, right heart failure in 21%, arrhythmia in 14%, syncope in 10%, and progressive isolated right ventricular dilatation in 7%. Heterograft prostheses were used in 33 patients and homografts in 9. Five patients underwent isolated pulmonary valve replacement; concomitant procedures performed in 37 patients included tricuspid valve repair/replacement (n = 18), residual ventricular septal defect repair (n = 12), atrial septal defect closure (n = 4), pulmonary artery patch angioplasty (n = 17), and right ventricular outflow tract enlargement (n = 13). One patient died early (2%) of multiorgan failure. There were 6 late deaths, 3 of which were cardiac related. Survival was 95.1% +/- 3.4% and 76.4% +/- 8.9% at 5 and 10 years, respectively. Functional class of patients was improved significantly; preoperatively, 76% of patients were in New York Heart Association class III-IV, and after pulmonary valve replacement, 97% of surviving patients were in class I-II (P =.0001). Moderate to severe reduction in right ventricular function was noted on preoperative echocardiography in 59% and on late echocardiography in 18% (P =.03). Of the 5 patients who had supraventricular arrhythmias before pulmonary valve replacement, 1 had postoperative recurrence and the arrhythmia is controlled with antiarrhythmic therapy; the other 4 are in normal sinus rhythm at late follow-up. Eight patients subsequently underwent pulmonary valve re-replacement without early mortality at a mean interval of 9.0 +/- 4.2 years (range 3.8-16.8 years). Freedom from pulmonary valve re-replacement was 93.1% +/- 4.7% and 69.8% +/- 10.7% at 5 and 10 years, respectively. The only significant risk factor for re-replacement was young age at the time of the initial pulmonary valve replacement (P =.023).

CONCLUSION

Late pulmonary valve replacement after tetralogy repair significantly improves right ventricular function, functional class, and atrial arrhythmias, and it can be performed with low mortality. Subsequent re-replacement may be necessary to maintain functional improvement.

Pediatric cardiac retransplantation: intermediate-term results

BACKGROUND

Cardiac retransplantation (re-CTx) in children is a controversial therapy, yet it remains the best treatment option to recipients with failing grafts. Our objective was to determine the incidence of re-CTx in a large pediatric population of recipients and evaluate the outcome of such therapy.

METHODS

Between November 1985 and November 1999, 347 children underwent cardiac transplantation at the Loma Linda University Medical Center. Of these, 32 children were listed for re-CTx. Ten patients died while waiting, and 22 recipients underwent re-CTx. Median age at re-CTx was 7.1 years (range, 52 days to 20.1 years).

RESULTS

Indications for re-CTx were allograft vasculopathy (n = 16), primary graft failure (n = 5), and acute rejection (n = 1). Two patients with primary graft failure underwent retransplantation within 24 hours of the first transplantation procedure while on extracorporeal membrane oxygenation support. Median time interval to re-CTx for the others was 7.2 years (range, 32 days to 9.4 years). Operative mortality for all cardiac re-CTx procedures was 13.6%. Causes of hospital mortality were pulmonary hypertension with graft failure (n = 2) and multiorgan failure (n = 1). Median hospital stay after re-CTx was 14.1 days (range, 6 to 45 days). There was one late death from severe rejection. Actuarial survival at 3 years for re-CTx was 81.9% +/- 8.9% compared with 77.3% +/- 2.6% for primary cardiac transplantation recipients (p = 0.70).

CONCLUSIONS

Elective re-CTx can be performed with acceptable mortality. Although the number of patients undergoing retransplantation in this report is small and their long-term outcome is unknown, the intermediate-term survival after re-CTx is similar to that of children undergoing primary cardiac transplantation.

Entrapment of subvalvular mitral tissue causing intermittent failure of a St Jude mitral prosthesis

Frequently portions of the mitral valve and sub-valvular apparatus are left intact during mitral valve replacement to help preserve left ventricular function. We describe a patient with paroxysmal congestive heart failure caused by intermittent entrapment of the subvalvular apparatus in the prosthesis, preventing complete valve closure.

Surgical treatment of valvular heart disease in patients with acromegaly

BACKGROUND AND AIM OF THE STUDY

Acromegaly is associated with heart disease in one-third of patients, and diastolic dysfunction may precede global systolic dysfunction. Patients with acromegalic heart disease may have valvular disease, but the role of surgery in such patients has not been established. The purpose of this study was to document the outcome of surgery in a series of these patients from one institution.

METHODS

Among 951 patients with the diagnosis of acromegaly seen at our institution since 1972, 10 (eight men, two women) have undergone operation for valvular heart disease. Average patient age was 62.2 +/- 11.5 years; average body weight was 84 +/- 13 kg; average height was 178 +/- 12 cm. The mean duration of acromegaly was 15.2 +/- 12.7 years. At the time of heart surgery, seven patients had active disease, defined by elevation of growth hormone levels, while three had inactive disease. Treatment of pituitary adenomas before valvular surgery included surgical resection in three patients and external-beam radiation treatment in four. The preoperative ejection fraction was 42 +/- 19% (range: 20% to 66%). Valve lesions included aortic stenosis in four patients, aortic regurgitation in four, and mitral regurgitation in three (one patient had double valve disease).

RESULTS

Valve replacement was performed in all patients with aortic disease (two bioprostheses, six mechanical), and three patients with mitral regurgitation had repair. Concomitant procedures performed in seven patients included coronary bypass (two), left ventricular aneurysmectomy (two), and ligation of the left atrial appendage, septal myectomy and defibrillator insertion (one each). Early complications included endocarditis, low cardiac output and arrhythmia in one patient each. There were no perioperative deaths. One patient underwent reoperation ten years later for a perivalvular leak.

CONCLUSION

Valvular surgery can be performed safely in acromegalic patients, even those with active endocrinopathy.

Heart transplantation for radiation-associated end-stage heart failure

Radiation-induced heart disease is an increasingly recognized late sequela of mediastinal radiation therapy for malignant neoplasms. We report four cases of heart transplantation for end-stage heart failure induced by mediastinal radiation therapy. Short-term and intermediate-term results are excellent with all four patients currently surviving a mean of 48 months after transplantation. Neither a second malignancy nor recurrence of the primary malignancy has been observed to date. The early results of heart transplantation for end-stage, radiation-induced heart disease are encouraging.

Operation for partial atrioventricular septal defect: a forty-year review

BACKGROUND

We describe the long-term outcome of repair of partial atrioventricular septal defect by determining the rates of survival, reoperation, and occurrence of left atrioventricular valve regurgitation, left atrioventricular valve stenosis, left ventricular outflow tract obstruction, and arrhythmia.

METHODS

We studied 334 patients who underwent repair of partial atrioventricular septal defect before 1995.

RESULTS

The 30-day and 5-, 10-, 20-, and 40-year survival were 98%, 94%, 93%, 87%, and 76%, respectively. Closure of the left atrioventricular valve cleft (P =. 03) and age less than 20 years at operation (P <.001) were associated with better survival. Reoperation was performed for 38 patients (11%). Repair of residual/recurrent left atrioventricular valve regurgitation or stenosis was the most common reason for reoperation. Left ventricular outflow tract obstruction occurred in 36 patients, and 7 patients underwent reoperation to relieve this obstruction. Supraventricular arrhythmias were observed in 58 patients (16%) after the operation. Supraventricular arrhythmias increased with increasing age at primary operation (P =.001). Complete atrioventricular block occurred in 9 patients (3%). Permanent pacemakers were implanted in 11 patients.

CONCLUSIONS

Long-term survival after repair of partial atrioventricular septal defect is good. It is important to close the cleft in the left atrioventricular valve. Reoperation for persistent or recurrent left atrioventricular valve malfunction and relief of left ventricular outflow tract obstruction is necessary in approximately 11% of patients.

Congenital Heart Surgery Nomenclature and Database Project: Ebstein's anomaly and tricuspid valve disease

Ebstein's anomaly is a rare congenital heart defect that is characterized by a spectrum of anatomical abnormalities of the tricuspid valve that also involve the right atrium and right ventricle. The extant nomenclature for Ebstein's anomaly and our approach to the description of the severity of Ebstein's anomaly are reviewed with the objective of establishing a unified reporting system. Although there are common features in Ebstein's anomaly, there is a wide spectrum of pathology with an infinite variety of combinations of severity of the involved structures. An effort was made to develop a classification system that would take into consideration the anatomic abnormalities that help direct the surgical management, particularly in regard to tricuspid valve repair or valve replacement. Isolated congenital tricuspid stenosis and regurgitation are also rare, and a simple classification system is presented. Acquired causes of tricuspid regurgitation and stenosis are more common and are included in the classification system. A comprehensive database set for these malformations is presented so that a comprehensive risk stratification analysis can be performed. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and risk factors are presented.

Measurement of blood serum cyclosporine levels using capillary "fingerstick" sampling: a validation study

Capillary blood sampling as a means of monitoring blood cyclosporine levels has replaced venipuncture in some medical centers. As the validity of capillary venipuncture for analysis of cyclosporine has not been documented, we sought to validate the capillary blood collection technique by comparing it with serum samples collected simultaneously by venous phlebotomy. Forty paired capillary- and venous samples were collected from 36 cardiac transplantation patients and analyzed, using a polyclonal immunoassay. The values obtained were compared using regression correlation. The correlation coefficient for all 40 samples was 0.859. However, we discovered that the first 7 capillary specimens were processed incorrectly. The correlation coefficient for the other 33 samples was 0.995 (99% confidence interval 0.987-0.998). The excellent correlation between serum samples obtained from capillary sampling and from venous sampling, together with the ease of obtaining capillary blood specimens, make "fingerstick" sampling the method of choice for monitoring cyclosporine levels in infants and children.

Ultra fast track in elective congenital cardiac surgery

BACKGROUND

Changes in healthcare delivery have affected the practice of congenital cardiac surgery. We recently developed a strategy of limited sternotomy, early extubation, and very early discharge, and reviewed the perioperative course of 198 pediatric patients undergoing elective cardiovascular surgical procedures, to assess the efficacy and safety of this approach.

METHODS

One hundred ninety-eight patients aged 0 to 18 years (median 3.2 years) underwent 201 elective cardiovascular surgical procedures over a 1-year period. All patients were admitted on the day of surgery. Patients were divided into six diagnostic groups: group 1, complex left-to-right shunts (n = 14, 7.0%); group 2, simple left-to-right shunts (n = 83, 41.3%); group 3, right-to-left shunts with pulmonary obstruction (n = 33, 16.4%); group 4, isolated, nonvalvular obstructive lesions (n = 30, 14.9%); group 5, isolated valvular anomalies (n = 20, 10.0%); and group 6, miscellaneous (n = 21, 10.4%).

RESULTS

After 201 procedures, 175 patients (87.1%) were extubated in the operating room and 188 (93.6%) within 4 hours from operation. Four patients (2.0%) were extubated more than 24 hours from completion of the procedure, and 2 (1.0%) died while on respiratory support (never weaned). Five patients (2.6%) failed early extubation (<4 hours). Early discharge was achieved for the vast majority of patients. Overall median length of stay (LOS, including day of surgery as day 1) was 2.0 days, with a median LOS of 3.0 days for those patients requiring circulatory arrest duration exceeding 20 minutes. Of 195 patients, 43 (24.6%), 121 (74.0%), and 159 (81.5%) were discharged, respectively, at <24, <48, <72 hours from admission. Longest and shortest mean postoperative LOS were in group 6 (9.9+/-14.5 days) and group 2 (1.6 = 0.7 days), respectively. Six patients (2.9%) died, and 11 (5.5%) suffered in-hospital complications. Thirty patients (15.4%) were either treated as outpatients (n = 11, 5.7%) or readmitted (n = 19, 9.7%) within 30 days from the time of surgery. Only 8 of 195 patients (4.1%) were readmitted with true surgical complications requiring invasive therapeutic procedures.

CONCLUSIONS

Selected patients with a broad spectrum of congenital heart disease may enjoy same-day admission, limited sternotomy, immediate extubation, and very early discharge with excellent outcomes and acceptable morbidity.

Idiopathic annular dilation: a rare cause of isolated severe tricuspid regurgitation

The management of patients with severe tricuspid regurgitation (TR) requires the clinician to clarify the mechanism of regurgitation. Primary disorders of the tricuspid valve, either congenital or acquired, may be readily identified by echocardiography. Severe TR most often results from left-sided heart disease and secondary pulmonary hypertension. Cardiomyopathic processes may also cause right ventricular failure and functional TR. We report three patients with severe TR due to idiopathic annular dilation. The tricuspid valves were otherwise normal on surgical inspection, and the pulmonary pressures were not significantly elevated. Each patient was aged over 65 years and had chronic atrial fibrillation with preserved left ventricular systolic function. Surgical treatment was associated with marked clinical improvement. Clinicians should recognize this unusual but treatable cause of right-sided congestive heart failure.

Cox-Maze procedure for atrial fibrillation: Mayo Clinic experience

The Cox-Maze procedure corrects atrial fibrillation in 90% of patients, and successful operation restores sinus rhythm, thereby reducing risks of thromboembolism and anticoagulant-associated hemorrhage. Symptoms such as palpitation and fatigability also improve with restoration of atrioventricular synchrony. At the Mayo Clinic, 221 Cox-Maze procedures were performed from March 1993 through March 1999. Over 75% of patients had associated cardiac disease and concomitant operations. Overall, early mortality was 1.4%, and the incidence of postoperative pacemaker implantation was 3.2%. Limiting incisions to the right atrium simplifies the operation for patients who primarily have tricuspid valve disease, and in early follow-up, outcome appeared to be as good as that achieved with biatrial incisions. The Cox-Maze procedure has proved particularly useful for patients with preoperative atrial fibrillation who require valvuloplasty for acquired mitral valve regurgitation; 87 patients have had this combined procedure, and there have been no early deaths. Further, our experience indicates that ventricular dysfunction is not a contraindication for operation and that restoration of sinus rhythm after the Cox-Maze procedure improves left ventricular ejection fraction in most patients.

Repair of anterior leaflet mitral valve prolapse: chordal replacement versus chordal shortening

BACKGROUND

To determine the optimal method of repair for severe, segmental anterior leaflet prolapse, we analyzed outcome of 121 patients who underwent chordal shortening (n = 46) and chordal replacement (n = 75) from 1988 to 1996.

METHODS

Chordae were replaced with expanded polytetrafluoroethylene sutures. Patients had an annuloplasty with either chordal replacement or shortening. Follow-up was 100% complete (mean, 3.7 years).

RESULTS

Mean age was 62.1 years, 86 were men, and 60 patients had isolated valve repair. There was one hospital death and 14 late deaths for a 5-year actuarial survival of 86.4%+/-4.5%. Sixteen patients underwent reoperation, 5 in the replacement group and 11 in the shortening group. Mechanism of valve failure in the replacement group was native chordae rupture (n = 4) and neochordae dehiscence (n = 1). With chordal shortening, repair failure was attributed to rupture of shortened chordae (n = 8), leaflet prolapse with and without annuloplasty ring dehiscence (n = 2), and native chordae elongation (n = 1). Risk of reoperation because of repair failure at 3.5 years was 1.4% in the chordal replacement group and 14.8% in the chordal shortening group (p = 0.02).

CONCLUSIONS

Chordal replacement is superior to chordal shortening, providing a predictable method for correction of mitral regurgitation with a low incidence of reoperation.

Mitral valve replacement or repair after previous coronary artery bypass grafting

BACKGROUND

Patients who have had previous CABG may subsequently develop significant mitral valve (MV) dysfunction that requires surgical intervention.

METHODS AND RESULTS

We reviewed 80 consecutive patients who had had previous CABG and who underwent MV surgery between January 1972 and March 1997. Forty-seven (59%) had initial CABG elsewhere, and 5 had had previous CABG twice. The mean interval between the previous CABG and the MV surgery was 6.3 years (range, 4.4 months to -17 years). At least 15 patients had grade 1/4 to 2/4 mitral regurgitation at initial CABG. The study group included 59 men and 21 women, with a mean study group age of 65.5 years. Ninety-four percent had symptoms of congestive heart failure, 60% had angina, 96% were in NYHA class III to IV, and 37% had an ejection fraction (EF) <50%. Origin of the MV disease was ischemic in 33 patients, myxomatous in 19, combined ischemic and myxomatous in 16, rheumatic in 5, infective in 3, and unknown in 4. MV repair was performed in 46 patients (58%) and MV replacement (MVR) in 34. Concomitant repeat CABG was performed in 38 (48%) patients. In-hospital mortality was 7 of 80 (8.8%); no early death occurred among patients with myxomatous disease. EF <50% was the only significant predictor of early mortality. Overall 1-, 5-, and 10-year survival was 83.8%, 55.6%, and 34.4% respectively. Predictors of late cardiac death were preoperative NYHA class IV (P=0.0006), urgent or emergency operation (P<0.0001), use of intra-aortic balloon pump (P=0.002), and EF <50% (P=0.01). Seven patients had an additional reoperation: 4 received CABG, 2 MVR, and 2 MV repair.

CONCLUSIONS

Ischemic, myxomatous, rheumatic, or infective MV dysfunction may develop subsequently after CABG. MVR or MV repair after previous CABG is associated with an acceptably low operative risk and good relief of symptoms. Left ventricular function is strongly correlated with both hospital and late mortality. Surgery should be done before LV dysfunction develops.

The role of gene therapy for intimal hyperplasia of bypass grafts

BACKGROUND

Proliferation of the intima is an early lesion of saphenous vein graft disease. Early patency rates of radial artery grafts are acceptable, but little is known about their risk of intimal hyperplasia.

METHODS AND RESULTS

To develop a model of intimal hyperplasia, we incubated human saphenous veins, internal mammary arteries, and radial arteries (n=6, 8, and 10, respectively) in an organ culture with Roswell Park Memorial Institute 1640 (30% serum) for 0, 4, 7, 10, and 14 days. Quantitative histological studies were performed, and the average intimal-to-medial (I/M) ratio was calculated for each incubation interval. After 10 and 14 days of culture, the I/M ratio increased in the saphenous veins (P=0. 03, P=0.04 versus 0 day, respectively). No significant increase occurred in the I/M ratio in either the internal mammary or radial arteries. Next, the ability of adenoviral gene transfers to inhibit intimal hyperplasia in the saphenous veins was evaluated. Adenoviral-mediated gene transfer of nitric oxide synthase significantly reduced the I/M ratio at 14 days compared with vehicle (P=0.001) and virus (P=0.004) controls.

CONCLUSIONS

The human saphenous vein has a greater propensity for intimal hyperplasia than arterial grafts; the human radial artery behaves similarly to the internal mammary artery. In the future, gene therapy may augment nitric oxide synthase, limiting vein graft disease.

Surgical patent foramen ovale closure for prevention of paradoxical embolism-related cerebrovascular ischemic events

BACKGROUND

The role of surgical closure of patent foramen ovale (PFO) for cerebral infarction (CI) or transient ischemic attack (TIA) resulting from paradoxical embolism is unclear, and its effect on recurrence is unknown. Our objective was to determine the outcome of surgical closure of PFO in patients with a prior ischemic neurological event, define the rate of CI or TIA recurrence after PFO closure, and identify risk factors for these recurrences.

METHODS AND RESULTS

We retrospectively analyzed 91 patients (58 men, 33 women) with >/=1 previous cerebrovascular ischemic events who underwent surgical PFO closure between April 1982 and March 1998. The presence of a PFO with a right-to-left shunt was confirmed with transesophageal echocardiography. Mean age was 44.2+/-12.2 years. The index event was a CI in 59 and a TIA in 32; a Valsalva-like episode preceded the event in 15 patients. Deep venous thrombosis was documented in 9 patients, and a hypercoagulable state was identified in 10. Surgical closure was performed with extracorporeal circulation by either direct suture (n=82) or patch closure (n=9). Limited incisions were used in 18.7% of patients. There was no operative mortality. Morbidity included transient atrial fibrillation (n=11), pericardial drainage for effusion (n=4), exploration for bleeding (n=3), and superficial wound infection (n=1). Follow-up totaled 176.3 patient-years, and mean follow-up was 2.0 years. No one had a CI, and 8 had a TIA during follow-up, with 1 caused by temporal arteritis. Transesophageal echocardiography demonstrated all closures to be intact in these patients. The overall freedom from TIA recurrence during follow-up was 92.5+/-3.2% at 1 year and 83.4+/-6.0% at 4 years. Having multiple neurological events before PFO closure was the only significant risk factor for TIA or CI recurrence after closure by univariate analysis (P=0.05); the small number of post-PFO closure cerebral ischemic events precluded multivariate analysis.

CONCLUSIONS

Surgical closure of PFO can be performed with minimal morbidity and mortality. PFO closure may decrease the risk of recurrent stroke or TIA and may avoid lifelong anticoagulation in the young adult if there is no other indication. Recurrent cerebrovascular ischemic events after surgery should prompt further evaluation to identify causes other than paradoxical embolism.

Isolated tricuspid valve surgery for severe tricuspid regurgitation following prior left heart valve surgery: analysis of outcome in 34 patients

BACKGROUND AND AIMS OF THE STUDY

Patients with symptoms of right heart failure due to severe tricuspid regurgitation following a prior operation on left heart valves present a difficult problem. The outcome of tricuspid surgery in this setting is not well defined. We describe a single-center experience of isolated tricuspid valve surgery after prior left heart valve surgery, and analyze potential risk factors for a poor outcome.

METHODS

Thirty-four patients who underwent isolated tricuspid valve operation for severe tricuspid regurgitation following prior valvular surgery for left-sided valve disease between 1980 and 1997 were identified. Charts were reviewed for clinical, echocardiographic, catheterization and surgical data. Follow up of survivors was conducted by telephone to ascertain functional status.

RESULTS

Three patients died in hospital (early mortality rate, 8.8%). At a follow up of 71 +/- 39 months, 13 patients were alive and 21 reached an end-point (three cardiac reoperations, 18 deaths). Event-free actuarial survival at five years was 41.6 +/- 9.2%. Patients who were alive at follow up had a mean NYHA functional class of 2.1 +/- 0.6 compared with 3.4 +/- 0.5 preoperatively; 85% of survivors were symptomatically improved. Predictors of poor outcome were: increased age at the time of tricuspid surgery (p = 0.0007) and higher number of prior cardiac operations (one versus two or three, p-value 0.01, relative risk 3.4). Pulmonary artery systolic pressure, left ventricular ejection fraction, right ventricular function and size, annulus diameter, tricuspid valve pathology, and valve replacement versus repair were not predictive of outcome.

CONCLUSIONS

Isolated tricuspid valve surgery for severe tricuspid regurgitation following prior surgery for left-sided heart valve disease can be performed with acceptable early mortality. There remains a high late mortality that is predicted only by age and the number of previous cardiac operations. However, in this selected group of severely symptomatic patients, significant improvement in symptoms are achieved in the survivors.

Clinical and echocardiographic characteristics of significant pericardial effusions following cardiothoracic surgery and outcomes of echo-guided pericardiocentesis for management: Mayo Clinic experience, 1979-1998

STUDY OBJECTIVES

This study assessed the clinical features, timing of presentation, and echocardiographic characteristics associated with clinically significant pericardial effusions after cardiothoracic surgery. The outcomes of echocardiographically (echo-) guided pericardiocentesis for the management of these effusions were evaluated.

DESIGN

From the prospective Mayo Clinic Registry of Echo-guided Pericardiocentesis (February 1979 to June 1998), 245 procedures performed for clinically significant postoperative effusions were identified. Clinical features, effusion causes, echocardiographic findings, and management outcomes were studied and analyzed. Cross-referencing the registry with the Mayo Clinic surgical database provided an estimate of the incidence of significant postoperative effusions and the number of cases in which primary surgical management was chosen instead of pericardiocentesis.

RESULTS

Use of anticoagulant therapy was considered a significant contributing factor in 86% and 65% of early effusions (< or =7 days after surgery) and late effusions (>7 days after surgery), respectively. Postpericardiotomy syndrome was an important factor in the development of late effusions (34%). Common presenting symptoms included malaise (90%), dyspnea (65%), and chest pain (33%). Tachycardia, fever, elevated jugular venous pressure, hypotension, and pulsus paradoxus were found in 53%, 40%, 39%, 27%, and 17% of cases, respectively. Transthoracic echocardiography permitted rapid diagnosis and hemodynamic assessment of all effusions except for three cases that required transesophageal echocardiography for confirmation. Echo-guided pericardiocentesis was successful in 97% of all cases and in 96% of all loculated effusions. Major complications (2%), including chamber lacerations (n = 2) and pneumothoraces (n = 3), were successfully treated by surgical repair and chest tube reexpansion, respectively. Median follow-up duration for the study population was 3.8 years (range, 190 days to 16.4 years). The use of extended catheter drainage was associated with reduction in recurrence for early and late postoperative effusions by 46% and 50%, respectively.

CONCLUSIONS

The symptoms and physical findings of clinically significant postoperative pericardial effusions are frequently nonspecific and may be inadequate for a decision regarding intervention. Echocardiography can quickly confirm the presence of an effusion, and pericardiocentesis under echocardiographic guidance is safe and effective. The use of a pericardial catheter for extended drainage is associated with lower recurrence rates, and the majority of patients so treated do not require further intervention.

Intraoperative application of power Doppler imaging: visualization of myocardial perfusion after anastomosis of left internal thoracic artery to left anterior descending coronary artery

The purpose of this study was to determine the role of power Doppler imaging in assessing patency of coronary artery bypass graft (CABG) anastomosis. Twelve consecutive patients referred for CABG with the use of anastomosis of the internal thoracic artery to the left anterior descending coronary artery (LAD) were studied. A linear 6.5-MHz wide-band transducer was used during cardioplegic administration and reperfusion. Baseline power Doppler signals were obtained in the LAD in 11 patients, and post-CABG signals were obtained in 11 patients. In one patient the LAD was poorly visualized because of extensive calcification. In another patient the flow after bypass worsened and the graft was revised. Visualization of the LAD and internal thoracic artery grafts by epicardial intraoperative power Doppler imaging is feasible in almost all patients and allows rapid and simple intraoperative assessment of graft patency. In addition, myocardial perfusion is limited by heavily calcified coronaries.

Coronary artery bypass grafting in patients with previous mediastinal radiation therapy

OBJECTIVES

Our objectives were to characterize the outcome of coronary artery bypass grafting in patients with previous mediastinal radiation therapy and to identify special features of this condition that relate to surgical management.

PATIENTS AND METHODS

We conducted a retrospective review of 47 patients (28 women, 19 men) with a mean age of 63.5 +/- 12.8 years (range 31.0-82. 9 years) from 1976 through December 1996 undergoing coronary artery bypass graft after mediastinal radiation therapy.

RESULTS

The mean interval between mediastinal radiation therapy and coronary artery bypass grafting was 15.1 +/- 9.8 years (range 1.1-37.8 years). In the 44 patients with isolated coronary surgery, operative mortality was 3 patients (6.8%). Sternal wound infection occurred in 3 patients (6.8%). Actuarial survival at 1 and 5 years was 87.2% +/- 4. 9% and 71.6% +/- 7.1%, respectively. Total follow-up was 293.7 patient-years (mean 6.2 +/- 5.1 years). There were 17 late deaths (malignancy, n = 7; heart failure, n = 6; stroke, n = 1; other noncardiac causes, n = 2; and sudden death, n = 1). Twelve of 43 discharged patients had the development of valvular disease demonstrated by follow-up echocardiography.

CONCLUSIONS

The early results of coronary artery bypass grafting for the treatment of ischemic heart disease after mediastinal radiation therapy are good. Late survival, however, is limited by malignancy, either recurrent or new, and the development of heart failure. Inasmuch as 25 other patients after radiation therapy required concomitant valve surgery and 12 of 43 (28%) discharged patients had later development of valvular disease, with 2 requiring reoperation, careful assessment of any valvular lesion is important during the initial coronary artery bypass grafting. Careful follow-up, including regular echocardiographic screening, is recommended in this patient population.

Endothelial regulation of vascular contraction in radial and internal mammary arteries

BACKGROUND

The extent to which the endothelium regulates radial artery (RA) contractions is unknown. The goals of this study were to characterize endothelium-dependent relaxations in the RA, compare these responses with those in the internal mammary artery (IMA), and, subsequently, manipulate nitric oxide production in the RA with adenovirus-mediated gene transfer.

METHODS

Segments of RA and IMA from 43 patients were studied initially in organ chambers. Endothelial function was evaluated and gene transfer, was examined.

RESULTS

After precontraction to 80% maximum tension with prostaglandin F2alpha, acetylcholine produced lesser relaxations in the RA (21.5%+/-5.8%) than in the IMA (66.7%+/-10.6%); human thrombin and adenosine 5'-diphosphate yielded similar results. Reduced relaxations in the RA (16.8%+/-4.2%) compared with those in the IMA (71.6%+/-11.9%) were noted with calcium ionophore. Superfusion bioassay demonstrated a similar baseline release in both arteries but a reduced stimulated production of vasoactive substances in the RA, results confirmed by cyclic guanosine monophosphate level determination. The RA produced less 6-keto-prostaglandin F1alpha than the IMA. Light microscopy demonstrated an intact endothelium in both arteries. Adenovirus-mediated gene transfer of nitric oxide synthase augmented relaxations of the RA to acetylcholine.

CONCLUSIONS

Reduced production of endothelium-derived relaxing factors suggests diminished endothelial regulation of vascular smooth muscle in the RA compared with the IMA. This finding may explain, in part, the predisposition to vasoconstriction in RA grafts.

Cardiac transplantation for end-stage congenital heart defects: the Mayo Clinic experience. Mayo Cardiothoracic Transplant Team

OBJECTIVE

To review the outcome of cardiac transplantation undertaken in patients with congenital heart defects.

MATERIAL AND METHODS

Between November 1991 and March 1998 at our institution, cardiac transplantation was performed in 16 patients with congenital heart disease (age range, 3 to 57 years; mean, 26.1). Preoperative diagnoses included univentricular heart (N = 4); complete transposition of the great arteries (N = 3); Ebstein's anomaly (N = 2); tetralogy of Fallot (N = 2); levotransposition (N = 2); dextrocardia, corrected transposition, ventricular and atrial septal defects, and pulmonary stenosis (N = 1); double-outlet right ventricle (N = 1); and hypertrophic obstructive cardiomyopathy (N = 1). All patients had undergone from one to five previous palliative operations.

RESULTS

Four patients required permanent pacemaker implantation during the first month postoperatively because of bradycardia; more than 2 years later, another patient required a permanent pacemaker because of sick sinus syndrome. In addition, one patient had an automatic implantable cardioverter-defibrillator. Three patients required reconstruction of cardiovascular structures with use of prosthetic material (Teflon patches or donor tissue) at the time of cardiac transplantation. Actuarial 1-, 2-, and 5-year survival was 86.2 +/- 9.1%. During the first year after transplantation, two deaths occurred--one at 41 days of putative vascular rejection and the second at 60 days of severe cellular rejection. All other patients are alive and functionally rehabilitated; the mean follow-up period has been 26.1 months (range, 2 to 89.6).

CONCLUSION

Cardiac transplantation for patients with congenital heart disease can be accomplished with a low perioperative mortality and an excellent medium-term survival despite the challenges presented by the technical difficulties during invasive diagnostic procedures and at operation and the need for adherence to long-term multiple-drug therapy in this patient population.

Cardiac retransplantation for graft vasculopathy in children: should we continue to do it?

BACKGROUND

Cardiac transplantation (CTx) has been established as an effective therapy for a variety of inoperable cardiac conditions in infants and children. However, graft vasculopathy (GV) has emerged as the main limiting factor to long-term survival of CTx recipients. The only treatment of severe GV is cardiac retransplantation (re-Tx). Controversy exists regarding the use of scarce donor organs for cardiac re-Tx.

OBJECTIVE

To compare the outcome of cardiac re-Tx for GV with that of primary CTx in children.

DESIGN

A 12-year retrospective cohort review.

SETTING

A university-affiliated children's hospital.

PATIENTS

All infants and children who underwent CTx (group 1, n = 322) had complete follow-up of 1389.7 patient-years. Graft vasculopathy was confirmed in 32 recipients (1.1-8.2 years after undergoing CTx). Thirteen patients died suddenly, 3 died waiting for cardiac re-Tx (1-17 days after relisting), 4 are pending cardiac re-Tx, and 12 (group 2) underwent cardiac re-Tx.

INTERVENTION

Cardiac re-Tx at a mean (+/- SD) interval from the first CTx of 6.3 +/- 1.8 years (range, 2.2-9.4 years). Two patients required additional aortic arch aneurysm repair with cardiac re-Tx.

RESULTS

When group 1 was compared with group 2, there was no significant difference in operative mortality (9.0% vs 8.3%; P = .9), rejection rate (0.98 vs 0.86; P = .1), and hospital stay (23.0 +/- 18.8 days vs 20.5 +/- 11.6 days; P = .65). Actuarial survival for groups 1 and 2 at 1 and 4 years was 84.3% vs 83.3% (P = .59) and 74.4% vs 83.3% (P = .85), respectively.

CONCLUSIONS

The surgical outcome and intermediate survival of cardiac re-Tx for GV and primary CTx are similar. Children with severe cardiac GV are at risk of sudden death and can benefit from early cardiac re-Tx.

Minimally invasive saphenous vein harvesting: endothelial integrity and early clinical results

BACKGROUND

Endoscopic harvesting of vein grafts may reduce wound complications but the effect on the venous endothelium is unknown. Endothelium-derived vasoactive substances may be important in vein graft disease prevention. We investigated the impact of endoscopic harvesting on the release of these factors and proceeded to evaluate the clinical applicability.

METHODS AND RESULTS

Porcine veins were harvested in either an endoscopic or open fashion. Superfusion bioassay from endoscopic veins had a similar basal secretion as control veins (6.5% +/- 1.5% versus 3.2% +/- 2.2%, respectively; n = 5, p = 0.39). Calcium ionophore A23187 stimulation was similar in both groups (24.6% +/- 5.1% versus 27.3% +/- 9.6%; n = 5, p = 0.68). Light and electron microscopy documented a normal endothelial monolayer in both groups with no endothelial cell or connective tissue loss. Encouraged by these results, 38 patients have subsequently undergone this procedure at our institution. Total operative time for harvesting 35 to 45 cm of saphenous vein was 62.3 +/- 5.3 minutes (range, 35 to 120 minutes). The procurement time in the most recent five patients was 41.6 +/- 3.3 minutes. Patients had little incisional pain, but did have mild ecchymosis.

CONCLUSIONS

Endothelial release of vasoactive substances after endoscopic harvesting is similar to that after the traditional, extended incision technique, and microscopy confirmed similar histology. These laboratory findings support the satisfactory early clinical experience with endoscopic harvesting of saphenous veins.

Aortic valve homografts in adults: a clinical perspective

Aortic valve replacement is a lifesaving measure in patients with severe aortic valve disease. In the United States, the most commonly used prostheses are the mechanical and bioprosthetic valves. With mechanical valves, long-term anticoagulation is necessary because of high thrombogenic potential. Bioprosthetic valves have a relatively high incidence of structural failure, especially in younger patients. Aortic valve homografts, derived from human heart donors or autopsy material, provide an alternative to mechanical or animal valves. The advantages of the homograft in comparison with the mechanical prostheses are the low incidence of thromboembolism without anticoagulation and lower valvular gradients in smaller sizes. Homografts are relatively resistant to endocarditis and are the valve of choice during active endocarditis. Their major mode of failure has been aortic regurgitation; however, recent advances in preservation and operative techniques have decreased this problem. Whether implantation of an aortic valve homograft should be the procedure of choice in subsets of patients remains controversial. Herein we review the history, techniques, results, complications, and current indications for aortic valve homografts.

Indications, effectiveness, and long-term dependency in permanent pacing after cardiac surgery

The purposes of this study were to define predictors of long-term pacemaker dependency in patients having permanent pacemakers implanted shortly after cardiac surgery, and to evaluate short- and long-term results and survival in this population. Data from 120 adult patients with implantation since 1980 were retrospectively analyzed. Acute and chronic complication rates (4.2% and 16.6%, respectively) were not higher than those expected in the general paced population. In addition, continuous rhythm was evaluated by use of pacemaker inhibition in a subgroup of 20 patients to verify the validity of clinical criteria for pacemaker dependency. Of the patients evaluated for dependency, 41% eventually became nondependent. Prolonged monitoring with an inhibited pacemaker confirmed the accuracy of our method of clinical evaluation of pacemaker dependency. Significant predictors of long-term pacemaker dependency were complete atrioventricular block as the indication and bypass time of > 120 minutes (by multivariate and univariate analyses, respectively). Postoperative complete atrioventricular block is the most important predictor of pacemaker dependency, enabling an earlier decision on permanent pacemaker implantation (no later than the sixth and the ninth postoperative days for wide-complex and narrow-complex escape, respectively). Further prospective studies are needed to define optimal implantation times for indications other than complete atrioventricular block.

Endoscopic saphenous vein harvesting: minimally invasive video-assisted saphenectomy

A technique of greater saphenous vein harvesting for coronary artery revascularization using an endoscopic approach is herein detailed. The saphenous vein is directly identified at the knee through a single incision. An endoscopic dissector is advanced proximally and distally along the course of the vein, ligating side-branches with clips. The vein is divided at the ends of dissection, dependent on patient anatomy, by either a counterincision, endoscopic clips, or ligation with an Endo-loop.

Results of allograft aortic valve replacement for complex endocarditis

METHODS

Between November 1985 and July 1995, 36 patients underwent allograft aortic valve replacement for endocarditis. The mean age of the 29 men and seven women was 53 years (range 25 to 79 years). Previous procedures included mechanical (n = 9), bioprosthetic (n = 5), and allograft (n = 2) aortic valve replacement, aortic valvotomy (n = 1), and orthotopic heart transplantation (n = 1). Infecting organisms were Staphylococcus and Streptococcus species in 69% of patients and fungi in 6%. Intraoperative findings demonstrated valvular vegetations (n = 25), annular abscesses (n = 25), and cusp destruction (n = 13). Complex reconstruction of the aortic anulus was required in 25 patients, and associated procedures included mitral valve repair (n = 2), mitral valve replacement (n = 3), coronary artery bypass grafting (n = 8), repair of ventricular septal defect (n = 4), left ventricular aneurysmectomy (n = 1), and repair of atrial septal defect (n = 1). Allograft valve insertion was performed by the scalloped technique in seven, intraaortic cylinder technique in 19, and allograft aortic root replacement in 10.

RESULTS

Follow-up was 100% complete at a mean of 2.6 +/- 2.8 years after valve replacement. Operative mortality was 13.8%. Complications included low cardiac output (n = 10), bleeding (n = 2), myocardial infarction (n = 1), stroke (n = 1), renal insufficiency (n = 2), respiratory insufficiency (n = 3), and heart block (n = 8). Late echocardiogram (mean 2.6 +/- 1.8 years) demonstrated grade III/IV aortic regurgitation in five patients. There were seven late deaths (five cardiac, not valve-related; two noncardiac). No patient has had recurrence of endocarditis. Actuarial survival at 5 years was 53.1% +/- 11.5%. Univariate analysis demonstrated prosthetic valve endocarditis to adversely affect late survival (p = 0.04). Cumulative risk of reoperation at 5 years was 8.0% +/- 5.6%.

CONCLUSION

Allograft aortic valve replacement facilitated reconstruction of complex aortic valve endocarditis with a low reoperation rate and no recurrent endocarditis in this series.

Comparison of techniques for implantation of aortic valve allografts

BACKGROUND

Various implantation techniques for allograft aortic valve replacement have evolved over the years. Our objective was to examine the effects of different implantation methods on subsequent valve performance and durability.

METHODS

Between May 1985 and January 1994, 137 patients underwent allograft aortic valve replacement. The first 59 aortic valve allografts were inserted by the freehand scalloped technique with removal of the aortic sinuses, and the last 78 valves were inserted by the cylinder technique, in which the aortic sinuses and sinotubular junction were retained. The mean age of the 91 men and 46 women was 53.7 years (range, 18 to 83 years). Preoperative diagnoses were aortic stenosis (n = 57), aortic regurgitation (AR, n = 40) and aortic stenosis/AR (n = 40); 27 patients had prior aortic valve operations and 1 patient had a previous heart transplantation. Active endocarditis was present in 29 patients. Associated procedures included coronary artery bypass (n = 33), ascending aneurysm repair (n = 4), left ventricular aneurysmectomy (n = 3), repair of atrial septal defect (n = 2), mitral valve repair or replacement (n = 6), and aortic root enlargement (n = 24). Follow-up was complete in 133 patients (97%) a mean of 4.9 years (range, 1 day to 9.8 years) after allograft aortic valve replacement.

RESULTS

Operative mortality was 6.5% for all patients but only 1.9% for patients without infection having isolated aortic valve replacement. Early echocardiography (mean of 8.4 days postoperatively) demonstrated no AR or mild AR and a mean gradient of 10.6 +/- 6.2 mm Hg in all patients. The cumulative risk of development of grade III or IV AR at 7 years postoperatively was 26.2% +/- 6.3% in the scallop group and 12.4% +/- 5.6% in the cylinder group (p = 0.4). Late postoperatively, transvalvular gradient by echocardiography was 13.1 +/- 9.4 mm Hg, and was similar in the two study groups. Late AR led to reoperation in 13 patients (22%) who had initial implantation with the scallop method and only 4 patients (5.4%) who had the valve inserted with the cylinder method. However, because duration of follow-up was longer for patients in the scallop group, cumulative risk of reoperation was similar at 5 years postoperatively (scallop, 13.7% [95% confidence interval, 76.7% to 95.8%]; cylinder, 11.5% [95% confidence interval, 75.5% to 99.1%]).

CONCLUSIONS

The insertion of an aortic valve allograft as a cylinder, retaining the sinotubular junction, appears to result in less aortic regurgitation at 7 years postoperatively, and with additional follow-up may result in less reoperation for AR.

Safety and therapeutic effectiveness of reinfused shed blood after open heart surgery

This prospective study was designed to determine whether use of nonwashed shed mediastinal blood exacerbated platelet and related hematologic dysfunctions after cardiopulmonary bypass, compared with the alternative use of autologous and homologous standard liquid preserved blood for volume support. Thirty-two patients undergoing cardiopulmonary bypass for open heart operations were randomized to receive either nonwashed shed mediastinal blood (group 1; n = 16) or liquid preserved packed red blood cells (group 2; n = 16) for transfusion therapy in the management of postoperative bleeding. Patient blood samples and bleeding times were obtained preoperatively, after cardiopulmonary bypass but before transfusions, 2 and 24 hours after transfusion, and on postoperative days 2, 3, and 7. Group 1 patients received an average of 710 +/- 90 mL (range, 300 to 1,700 mL) of nonwashed shed mediastinal blood containing significantly greater (p < 0.0001) amounts of fibrin degradation products and D-dimer protein. Of the hematologic, microaggregate, and plasma protein measurements performed, only the protein C level was significantly greater in group 1 (p < 0.05) after transfusion. Patient bleeding times were not significantly different between the groups at any of the time points, and the total postoperative blood loss was not different between the groups. There was a trend toward less need for homologous transfusion in group 1 (p < 0.1). This study documents the safety and ease of using nonwashed shed mediastinal blood as a primary blood volume support after an open heart operation.

Metabolic correlates of myocardial stunning and the effect of cardiopulmonary bypass

In order to study the metabolic consequences of myocardial stunning, repeated coronary occlusions were performed in dogs. The production of CO2, adenosine triphosphate (ATP), phosphocreatine (PCr), and inorganic phosphate (Pi) by myocardial cells was assessed, along with extracellular and intracellular pH. Our results indicate that regional coronary artery occlusion reduces the ability of the myocardium to produce H+ and CO2 and to replenish ATP post ischemia. These alterations, then, represent the hallmark of metabolic viability during periods of ischemic insult. Decreases in PCr and Pi were completely eliminated during reperfusion and, therefore, are ot reflective of myocardial stunning. When normothermic cardiopulmonary bypass (CPB) is instituted and the coronary artery is occluded three times with reperfusion between each occlusion, alterations in myocardial H+ and high energy phosphates are identical to those observed using only repetitive coronary occlusion. Systemic hypothermia during CPB does not protect against myocardial stunning; however, it is anticipated that interventions that prevent the reduction in H+ and ATP levels may overcome the effects of myocardial stunning that occur during cardiac surgery.

Electrode-derived myocardial pH measurements reflect intracellular myocardial metabolism assessed by phosphorus 31-nuclear magnetic resonance spectroscopy during normothermic ischemia

To determine the ability of extracellular myocardial tissue pH measured with an intramural electrode to reflect myocardial intracellular metabolic status during normothermic ischemia, we studied 14 open-chest dogs with in vivo phosphorus 31-nuclear magnetic resonance spectroscopy during left anterior descending coronary artery occlusion (experimental group, group I, n = 7) or after a sham operation (control group, nonischemic, group II, n = 7). Phosphorus nuclear magnetic resonance spectra were acquired every 5 minutes at 4.7 tesla (256 averages, TR = 1000 msec, pulse width = 30 microseconds) with a 2 cm two-turn radiofrequency surface coil. Intracellular myocardial adenosine triphosphate peak area was normalized to an external phosphate standard. The change in adenosine triphosphate peak area was expressed as percent of baseline value. During 3 hours of normothermic ischemia the observed extracellular myocardial pH correlated with nuclear magnetic resonance-calculated myocardial pH in the ischemic dogs with an average r value of 0.94 (p less than 0.0001). During this same interval, the fall in extracellular myocardial pH correlated with the loss of adenosine triphosphate peak in each ischemic dog, with an average r value of 0.91 (p less than 0.0001). Thus extracellular myocardial pH, measured with an intramural electrode, correlated with nuclear magnetic resonance-derived myocardial pH and loss of myocyte adenosine triphosphate peak content and reflected the metabolic status of the myocyte during ischemia. These data validate the use of extracellular myocardial pH to assess the adequacy of myocardial preservation during aortic crossclamping for cardiac operations.