Maximizing prosthetic valve size with the Top Hat supra-annular aortic valve.

BACKGROUND AND AIM OF THE STUDY: The CarboMedics Top Hat supra-annular aortic valve allows a one-size (and often two-size) increase over the standard intra-annular valve. This advantage should minimize the risk of patient-prosthesis mismatch, where the effective prosthetic valve orifice area is less than that of a normal valve. It is suggested that the ability to implant Top Hat valves having greater size, relative to standard intra-annular valves, may currently be under-utilized. Further, there has been some concern that Top Hat implantation can cause obstruction of the coronary ostia. This study evaluates the authors' clinical experience with Top Hat supra-annular aortic valve size selection, and the technical aspects of implantation. METHODS: Between January 1999 and October 2005, a total of 251 consecutive patients underwent 252 aortic valve replacements with Top Hat supra-annular mechanical prostheses (CarboMedics, Inc., Arvada, CO, USA) at two institutions. Size frequency distribution was compared to published series, and to the manufacturer's US registry. The ventriculoaortic junction (VAJ) size was available in 234 patients, and compared to the size of the Top Hat valve implanted. RESULTS: Valves implanted were 2 mm larger than the VAJ in 56% of patients (130/234), 3 mm larger in 1.7% (4/234), and 4 mm larger in 42% (98/234). Numbers of 19-mm and 21-mm valves were less (p <0.001) in the present series (22%) than in published series (52%) and the US registry (46%). No patient required unplanned coronary bypass, and 30-day mortality was 2.0% (5/251), indicating a good safety profile for the valves implanted in this series. CONCLUSION: The general distribution of implant sizes in the US indicates that cardiac surgeons may be under-sizing the Top Hat supra-annular aortic valve during aortic valve replacement, thereby missing the full advantage of its unique design for lowering the transvalvular gradient and, consequently, left ventricular workload, leading to a reversal of left ventricular hypertrophy.

Use of recombinant activated factor VII for bleeding following operations requiring cardiopulmonary bypass.

Postoperative bleeding is a common complication following cardiothoracic surgical procedures requiring cardiopulmonary bypass (CPB). Serious bleeding complications requiring the administration of blood products, hemostatic drugs, and even repeat surgery are associated with considerable morbidity, mortality, and resource consumption. Therapy with recombinant activated factor VII (rFVIIa) may be an effective treatment strategy for patients with refractory bleeding. We report the successful use of rFVIIa for the treatment of intractable postoperative bleeding following aortic aneurysm repair in two patients with Marfan syndrome. In both patients, surgical reexploration was avoided, and the patients' clinical status was stabilized after the administration of rFVIIa. In one patient, hemostasis was rapidly achieved within minutes, whereas hemostasis occurred gradually over several hours in the second patient. Including our personal experience with the two cases, the use of rFVIIa has been reported in 20 patients who required CPB for cardiothoracic surgical procedures. Hemostasis was achieved in all patients. In 14 patients (70%), rapid hemostasis was achieved following a single dose of rFVIIa (mean dose, 57 microg/kg). In the remaining six patients, gradual hemostasis was achieved after a mean of 3.4 doses (mean cumulative dose, 225 microg/kg). Two patients (10%) were believed to have experienced thromboembolic complications after the administration of rFVIIa (one was fatal), and, in another patient, intracoronary thrombosis was suspected but was not confirmed. In patients experiencing postoperative bleeding complications that are refractory to treatment with blood products, hemostatic agents, and/or repeat surgery, the use of rFVIIa may be considered.

Outcome of coronary artery bypass operations in patients with renal insufficiency with and without renal transplantation.

HYPOTHESIS: Renal insufficiency (RI) is associated with an increased risk of morbidity and mortality following coronary artery bypass graft (CABG) operations, particularly among patients who are dependent on dialysis. DESIGN AND SETTING: A retrospective analysis of data collected at a tertiary care center. PATIENTS: One hundred eighty-four consecutive patients with RI who underwent CABG surgery between 1992 and 2004. This group consisted of 152 patients with serum creatinine levels of > or = 1.7 mg/dL (group I) and 32 kidney transplant recipients (group II). Of the patients in group I, 90 were dialysis-free (subgroup IA) and 62 were dialysis-dependent (subgroup IB). MAIN OUTCOME MEASURES: Demographics, perioperative data, and outcomes for each of the three groups were evaluated and compared. RESULTS: Fifty-four percent of the patients were in New York Heart Association classes III and IV, 36% had unstable angina, and 21% had left main coronary disease. The mean ejection fraction was 38%. The median postoperative length of stay in the hospital was 10 days. Of the patients in group IB, 8% required reexploration for bleeding compared to 3% in groups IA and II (p < 0.05). Dialysis was needed postoperatively in five patients in group IA and two patients in group II (5.7%). The raw operative mortality rate was 7.6% and was higher in group IB (9.7%) compared to groups IA and II (6.7% and 6.2%, respectively; p < 0.05). The actuarial 5-year survival rate was higher in group II compared to group I (79% vs 59%, respectively; p < 0.05). The difference in survival rates was more apparent between groups II and IB (79% vs 57%, respectively; p < 0.005). CONCLUSIONS: CABG is associated with an increased rate of perioperative complications and mortality in patients with RI. Dialysis dependence is a major risk factor for patients undergoing CABG surgery. However, with acceptable surgical results, dialysis patients should not be denied CABG surgery. A survival advantage is demonstrated among patients with previous kidney transplants compared to those patients who are dependent on dialysis.

Cardiac transplantation in patients with iron overload cardiomyopathy.

A review of the published world experience with heart transplantation for iron overload cardiomyopathy (IOC) between 1967 and 2003 as well as review of unpublished cases from the database of the United Network for Organ Sharing since 1992, identified a total of 16 patients (14 men and 2 women). Mean age was 31 years (range, 14-63 years). IOC etiology was hemochromatosis in 11 patients (69%), thalassemia major in 4 (25%), and Diamond-Blackfan anemia in 1 (6%). The 30-day mortality was 12%. Three patients (19%) died within 1 year of the transplant, all of infectious complications. An additional patient died at 7.14 years (unknown cause). The actuarial Kaplan-Meier 1-, 3-, and 5-year survival rates were 81% for all 3 time intervals. The actuarial 10-year survival was 41%.

Primary neuroendocrine tumors of the thymus.

Primary neuroendocrine tumors of the thymus are highly aggressive tumors that rarely occur. A little more than 200 cases have been reported, many of which were single case reports. Only a few articles contained modest series from single centers for analysis. A review of 157 cases collected from the major series reported to-date show a clinical pattern with male preponderance (male:female ratio, 3:1) and a mean age of 54 years. Most patients presented with symptoms and signs of local compression. Almost 50% of these tumors were functionally active and were associated with endocrinopathies. Several histologic variants have been described, all with similar ultrastructural features. The biologic behavior of these tumors shows a direct relation to the degree of differentiation. Whenever possible, surgical resection is the treatment of choice as adjuvant therapy is controversial and has been used with variable success. Potential therapies exploit the presence of somatostatin receptors on a variety of these tumors. Use of radiolabeled Octreotide for radionuclide therapy has yielded tumor inhibition in animal models and may have clinical application. Fifty-one percent of the patients survived 3 years, 27% survived 5 years, and less than 10% survived beyond 10 years. Histologic grade, tumor extension, and early detection are the most important factors affecting survival. Other prognostic factors that impact outcome include presence of endocrinopathy, incomplete resectability, nodal status, and presence of distant metastasis.

Late presentation of retained intracardiac ice pick with papillary muscle injury.

An unusual case of a penetrating intracardiac injury is described in a 16-year-old boy who presented with a retained 14-cm segment of an ice pick that went unnoticed by the patient for 4 days. The ice pick had lacerated the anterior papillary muscle of the left ventricle causing avulsion of its tip and prolapse of the anterior leaflet of the mitral valve resulting in severe mitral regurgitation. The urgency for surgical correction of the traumatic mitral valve injury at the time of extraction of the intracardiac foreign body through a single-stage approach versus a two-stage approach is discussed.

Mechanisms and future directions for prevention of vein graft failure in coronary bypass surgery.

Coronary artery bypass grafting has been utilized as a beneficial treatment for myocardial ischemic disease for over three decades. Failure of coronary artery venous grafts occurs at a substantial rate and has a large impact on two main endpoints, survival and quality of life. An exhaustive amount of basic research has been generated to delineate possible mechanisms responsible for graft failure and modalities to prevent its occurrence. Although pharmacotherapy exists, insufficient translation has emerged from the bench to the operating room. In this article, we review the literature regarding the current mechanisms and mediators including growth factors, nitric oxide and genetics leading to saphenous vein graft occlusion. The review addresses the current state of affairs and modes for prevention of vein graft failure perioperatively and newer technologies that may help ameliorate this problem in the future.

Midterm evaluation of hemodynamics of the Top Hat supraannular aortic valve.

The CarboMedics Top Hat supraannular aortic valve provides an orifice-to-annulus ratio of 1:1 in most patients, and enhances patient outcomes. This study compared the midterm echocardiographic parameters of 52 patients undergoing aortic valve replacement with a Top Hat valve with those in other studies of Top Hat or CarboMedics intraannular valves. Echocardiography was performed 6-48 months after surgery with Top Hat sizes 21-27. Parameters evaluated included mean gradient, peak gradient, effective orifice area, and effective orifice area index. Preoperative and postoperative echocardiographic measurements were compared in 38 patients with aortic valve stenosis. Hemodynamic data were comparable to those of other studies, but the Top Hat prosthesis implanted was significantly larger (by a mean of 3.29 mm) than the valve size indicated using an intraannular valve sizer in 48 patients. Mean effective orifice area improved significantly from 0.73 cm(2) preoperatively to 2.04 cm(2) postoperatively. In patients with preoperative aortic valve stenosis, postoperative mean peak gradient was significantly reduced. The larger orifice-to-annulus ratio of the Top Hat valve improved hemodynamic parameters assessed by echocardiography up to 4 years postoperatively, with a lower transvalvular gradient, hence decreased left ventricular workload.

Current status of the surgical treatment of atrial fibrillation.

Atrial fibrillation (AF) affects several million patients worldwide and is associated with a number of heart conditions, particularly coronary artery disease, rheumatic heart disease, hypertension, and congestive heart failure. The treatment of AF and its complications is quite costly. Atrial fibrillation usually results from multiple macro-re-entrant circuits in the left atrium. Very frequently, particularly in association with mitral valve disease, these circuits arise from the area of the junction of the pulmonary venous endothelium and the left atrial endocardium. Pharmacological therapy is at best 50% effective. Therapeutic options for AF include antiarrhythmic drugs, cardioversion, atrioventricular (A-V) node block, pacemaker insertion, and ablative surgery. In 1987, Cox developed an effective surgical procedure to achieve ablation. Current ablative procedures include the classic cut-and-sew Maze operation or a modification of it, namely through catheter ablation, namely, cryoablation, radiofrequency ablation (dry or irrigated), and other forms of ablation (e.g., laser, microwave). These procedures will be described, along with the indications, advantages and disadvantages of each. Special emphasis on the alternative means to cutting and sewing to achieve appropriate effective atrial scars will be stressed, and our experience with these approaches in 50 patients with AF and associated cardiac lesions and their outcomes is presented.

Biatrial primary synovial sarcoma of the heart.

Synovial sarcomas that primarily arise from the heart and pericardium are extremely rare, especially the ones involving both sides of the heart. To date, few cases have been reviewed in the literature. Our patient was a 36-year-old man who presented with primary biatrial synovial sarcoma that also involved the tricuspid annulus, heart valves, and interatrial septum. The tumor was debulked to relieve the atrioventricular obstruction. Molecular analysis confirmed the diagnosis of synovial sarcoma with positive t (X;18) SYT-SSX gene fusion. The patient is currently receiving chemotherapy. From our review of the 20 cases thus far reported in the English-language medical literature, the tumor more frequently affects young male patients, and carries a poor prognosis. Early detection is difficult because of the aggressive nature of the tumor. Like other sarcomas, wide surgical resection remains the mainstay of therapy. Adjuvant radiation therapy for local recurrence and chemotherapy for control of systemic disease may have some beneficial effect on overall survival, but the benefit is likely limited.

Recent developments in antithrombotic therapy: will sodium warfarin be a drug of the past?

Warfarin and heparin have formed the mainstay in the prophylaxis of deep vein thrombosis (DVT), stroke prevention in atrial fibrillation, and treatment of thromboembolic disease (TED). However, these choices are hampered by difficult administration, interactions with other medications, side effect profile, and limited indications for treatment. Anti-factor Xa (anti-Xa) inhibitors have already entered the drug market with the drug Fondaparinux being the first anti-Xa inhibitor to be approved for use in the U.S. by the Food and Drug Administration (FDA), and other drugs such as idraparinux being currently in development. A new class of medications, known as direct thrombin inhibitors (DTI), includes the parental agents lepirudin, argatroban and bivalirudin which have been approved by the FDA and the oral agents ximelagatran, melagatran and dabigatran. The latter three drugs which are oral DTIs may soon replace warfarin and heparin as the preferred medications for DVT prophylaxis and for reducing the relative risk of stroke. These drugs do not rely on blocking serine proteases nor do they require a co-factor (antithrombin III) like unfractionated heparin (UFH) or low molecular weight heparin (LMWH). DTIs are rapid in onset, easy to administer, do not interact with other medications or foods, have limited side effects, and can be administered in a fixed dose. The DTI ximelagatran has already been approved in several European and Asian countries, and over a dozen randomized clinical trials have been conducted demonstrating its performance to be on par with warfarin. However, approval by the FDA in the U.S. remains pending in view of reported incidences of elevations in hepatic enzymes that are currently under evaluation. This review examines the role of DTIs in the prevention and treatment of TED and the recent patents reported in the literature.

Surgical considerations in the correction of valve dysfunction following heart transplantation.

Valve dysfunction is not an uncommon occurrence following heart transplantation but when present can be managed medically with diuretics and vasodilator therapy. If medical therapy fails, these patients are considered for retransplantation. Due to the scarcity of donor hearts, efforts aimed at limiting the pool of cardiac retransplantation candidates are being focused lately on preservation of cardiac allograft function by conventional operations in lieu of a retransplant. A review of the literature for patients who underwent valve operations following their heart transplants yielded 26 cases. Four of these had isolated mitral valve procedures, 18 had tricuspid procedures, two had combined mitral and tricuspid operations and two had aortic valve replacements. In this communication, we present a case of severe aortic insufficiency developing 7 yr after heart transplantation and leading to progressive clinical deterioration and NYHA class IV heart failure symptoms. The aortic valve was replaced with a 21-mm Carbo Medics supra-annular mechanical prosthesis (CarboMedics Inc.). She had a favorable postoperative course and remains well 7 months after her operation. Surgical correction of valvular lesions is warranted if the function of the previously transplanted heart is reasonably preserved.

Outcome of heart transplantation in patients with amyloid cardiomyopathy.

BACKGROUND: We retrospectively reviewed the United Network for Organ Sharing (UNOS) database to assess the survival of patients with amyloidosis who were treated by heart transplantation. METHODS: Over a 15-year period, 69 patients had received orthotopic heart transplants and were entered into the database with the diagnosis of amyloidosis. The cohort consisted of 38 men and 31 women. Mean age was 51 years. RESULTS: There were 5 operative deaths and 29 late deaths at a mean follow-up of 40 months. Nine patients died of amyloid-related complications, and one developed graft vasculopathy and was retransplanted. CONCLUSIONS: Survival was influenced by recipient's sex (1-year survival 84% for men vs 64% for women, p = 0.003) but not by transplant era, ischemia time, or UNOS status.

The US experience with lung transplantation for pulmonary lymphangioleiomyomatosis.

PURPOSE: Lung transplantation has been increasingly used as a treatment modality for patients with pulmonary lymphangioleiomyomatosis (LAM). In this study, we evaluated the outcome of patients with LAM who underwent lung transplantation with the aim of making some recommendations regarding patient management. METHODS: We conducted a retrospective review of 79 patients who underwent primary lung transplantation for end-stage pulmonary LAM at 31 US transplant centers between January 1987 and December 2002 and were reported to the United Network for Organ Sharing (UNOS). RESULTS: All patients were women with a mean age of 41.1 years (range, 24-65 years). Thirty-four patients (43%) received single-lung transplants. Bilateral lung transplantation was performed in 45 patients (57%). The mean cold ischemia time was 4.7 hours. There were 2 intra-operative deaths. The 30-day mortality was 5% (4 patients). The causes of early death were primary graft failure in 2 patients, hyperacute rejection in 1 patient, and a cardiac event in 1 patient. Twenty late deaths (>30 days post-transplant) occurred. Of those, 5 were from multisystem organ failure, 5 from pulmonary complications, and 2 from fungal infection. Rejection and bronchiolitis obliterans accounted for 2 deaths each. The cause of death was a cardiac event in 1 patient and was not recorded in the remaining 3. Four patients were re-transplanted. Fifty-five patients (70%) were alive at a mean follow-up of 37 months (range 0-128 months). The actuarial Kaplan-Meier survival was 85.75% at 1 year, 76.35% at 3 years, and 64.91% at 5-years. Log-rank analysis showed a statistically significant difference in the survival rate of LAM patients compared with a historical group of patients who had transplantation for all lung conditions during the same period (45.12%, p = 0.0012). Transplant era, type of transplant, donor gender, ischemia time of more than 4 hours, age more than 40 years, and donor/recipient cytomegalovirus did not impact survival. CONCLUSIONS: Lung transplantation is a valuable therapeutic option for patients with end-stage pulmonary LAM. Transplantation offers survival rates that are equivalent to or better than those of patients who received a lung transplant for other indications.

Outcomes of lung transplantation in patients with scleroderma.

Patients with pulmonary insufficiency due to scleroderma have long been considered suboptimal candidates for lung transplantation. This has been supported by small single-center experiences that did not reflect the entire U.S. experience. We sought to evaluate the outcome of patients with scleroderma who underwent lung transplantation. We conducted a retrospective review of 47 patients with scleroderma who underwent lung transplantation at 23 U.S. centers between 1987 and 2004 and were reported to the United Network for Organ Sharing. Women constituted 57% of the patients. The mean age was 46 years. Twenty-seven patients received single lung transplants (57%), and the remaining received double lung transplants. The mean cold ischemia time was 4.1 hours. There were 7 early deaths (< or =30 days) and 17 late deaths (> 30 days). The causes of early death were primary graft failure and a cardiac event in two patients each and bacterial infection and stroke in one patient each. Late mortality was due to infection in seven patients, respiratory failure in three, malignancy in two, and multisystem organ failure, rejection, pulmonary hypertension, and a cardiac event in one patient each. The causes of early and late death were not recorded for two patients. One patient received a second transplant owing to graft failure of the first. Twenty-three patients (49%) were alive at a mean follow-up of 24 months. The Kaplan-Meier 1- and 3-year survival rates were 67.6% and 45.9% respectively, which are not significantly different from those of 10,070 patients given transplants for other lung conditions during the same period (75.5% and 58.8% respectively, P = 0.25). Donor gender, recipient's age, and type of transplant did not affect survival. In carefully selected patients with scleroderma who have end-stage lung disease, lung transplantation is a valid life-saving therapeutic option. Available data suggest acceptable short-term morbidity and mortality and a long-term survival similar to that of patients given transplants for other lung conditions.

Depressed cardiac myofilament function in human diabetes mellitus.

Diabetes mellitus is associated with a distinct cardiomyopathy. Whether cardiac myofilament function is altered in human diabetes mellitus is unknown. Myocardial biopsies were obtained from seven diabetic patients and five control, nondiabetic patients undergoing coronary artery bypass surgery. Myofilament function was assessed by determination of the developed force-Ca2+ concentration relation in skinned cardiac cells from flash-frozen human biopsies. Separate control experiments revealed that flash freezing of biopsy specimens did not affect myofilament function. All patients in the diabetes mellitus cohort were classified as Type 2 diabetes mellitus patients, and most showed signs of diastolic dysfunction. Diabetes mellitus was associated with depressed myofilament function, that is, decreased Ca2+ sensitivity (29%, P < 0.05 vs. control) and a trend toward reduction of maximum Ca2+-saturated force (29%, P = 0.08 vs. control). The slope of the force-Ca2+ concentration relation (Hill coefficient) was not affected by diabetes, however. We conclude that human diabetes mellitus is associated with decreased cardiac myofilament function. Depressed cardiac myofilament Ca2+ responsiveness may underlie the decreased ventricular function characteristic of human diabetic cardiomyopathy.

Surgical repair of mechanical complications of myocardial infarction.

Mechanical complications of acute myocardial infarction are estimated to account for 25,000 fatalities yearly in the United States. The diagnosis necessitates a high degree of clinical suspicion. Once recognized, prompt surgical intervention is necessary because if left untreated the condition frequently causes a fatal outcome. The main determinants of survival are the preoperative hemodynamic status of the patient, the presence of multisystem failure at presentation, and concomitant revascularization during repair of the defect. Because ischemic heart disease remains the leading cause of death in such patients following repair, coronary artery bypass should be considered and, whenever possible, performed in conjunction with repair of the postinfarct mechanical complication.