Albert Guerraty

Does Off-Pump Coronary Artery Bypass Reduce the Incidence of Clinically Evident Renal Dysfunction After Multivessel Myocardial Revascularization?

In this prospective, observational trial, we determined whether off-pump coronary artery bypass (OPCAB) was associated with less postoperative renal dysfunction (RD) compared with coronary bypass surgery with cardiopulmonary bypass (CABG). All patients undergoing primary, isolated coronary surgery at our institution in the year 2000 participated. Data collected on each patient included demographics, preoperative risk factors for RD, perioperative events, and serum creatinine concentrations from date of admission until discharge or death. The criteria for RD was both a ≥50% increase from preoperative creatinine and an absolute postoperative creatinine ≥2.0 mg/dL (177 &mgr;M). Student’s t-test or the Fisher’s exact test was used to compare groups. Stepwise multiple logistic regression identified determinants of RD; P < 0.05 significant. The CABG group (n = 119) differed from the OPCAB group (n = 220) with respect to age (64 ± 13 versus 67 ± 10 yr, P = 0.0074) and number of distal grafts (median 4 versus 3, P = 0.0003). Type of operation did not associate with the presence of postoperative RD: 18 (8.2%) of 220 OPCAB patients versus 12 (10%) of 119 CABG patients (P = 0.55). Our data suggest that choice of operative technique (OPCAB versus CABG) is not associated with reduced renal morbidity.

Cardiac transplantation with corticosteroid-free immunosuppression: Long-term result

To assess the long-term safety of an immunosuppressive regimen without corticosteroids, we retrospectively evaluated 42 long-term (greater than 1 year) survivors of orthotopic cardiac transplantation. We determined the incidence of (1) conversion of the immunosuppressive regimen from cyclosporine and azathioprine alone (group I) to cyclosporine, azathioprine, and prednisone (group II), (2) late acute graft rejection (defined as occurring at greater than 1 postoperative year), and (3) major postoperative complications related to corticosteroids. Of the 42 patients who were started on cyclosporine and azathioprine, 48% remained in group I, and 52% converted to group II. Forty-five percent of group II patients were able to taper and discontinue prednisone in 15.6 +/- 2.2 months. Among the patients on long-term corticosteroid-free immunosuppression, the incidence of late rejection was 2.1% per endomyocardial biopsy. The incidence of late infectious episodes was not significantly different between the two groups of patients, although diabetes mellitus and hypercholesterolemia were more prevalent in group II than in group I. These data suggest that cardiac transplant recipients who chronically remain on corticosteroid-free immunosuppression represent a select group of patients with an acceptably low risk of late graft rejection and associated reduction of potential risk factors of accelerated coronary artery disease.

Atrioventricular Fistula: An Unusual Complication of Endomyocardial Biopsy in a Heart Transplant Recipient

Endomyocardial biopsy remains the primary method for diagnosis of cardiac allograft rejection. Generally, endomyocardial biopsy is considered a relatively safe procedure in heart transplant recipients. Complications that have been reported are related to catheter insertion and include carotid arterial puncture, prolonged bleeding, vasovagal reaction, ventricular tachyarrhythmias, and transient conduction abnormalities. Serious complications such as right ventricular perforation with cardiac tamponade may also occur. Most complications are usually without significant long-term sequelae. This report describes an unusual case of atrioventricular fistula between the right atrium and left ventricle that occurred during a routine endomyocardial biopsy in a heart transplant recipient. Sudden hemodynamic compromise developed in this patient soon after heart biopsy associated with hemodynamic picture of high-output heart failure. Right heart catheterization, including oximetry, peripheral venous contrast echocardiography, color flow Doppler studies, and transesophageal echocardiography confirmed the diagnosis of fistulous communication between the right atrium and left ventricle, most likely through the membranous interventricular septum. Conservative medical management resulted in striking clinical improvement within 48 hours commensurate with spontaneous closure of the right atrium-to-left ventricle fistula documented by hemodynamic and echocardiographic studies.

Echocardiographic evaluation of patients with a left ventricular device.

Limited donor heart availability is primarily responsible for the renewal of interest in mechanical left ventricular assist devices (LVADs) as a bridge to transplantation. Donor availability is unlikely to increase significantly in the near future. Experience to date has shown that many patients can be maintained long enough to undergo transplantation, and LVADs may be acceptable as alternate therapy in some who may not be candidates for transplantation. However, criteria for noninvasive evaluation of patients on LVADs have not been developed. In a prospective study using serial echocardiography, we found that aortic valve opening, aortic forward flow, nonlaminar flow in the left ventricle, and mismatch of Doppler derived cardiac output at the pulmonic valve and device output are associated with device malfunction. Echocardiography was diagnostic in five of six patients with clinical instability unrelated to the device. These findings suggest that echocardiography is helpful in the routine evaluation of patients on LVADs.

Defining the limits of suitability of cardiac allografts

n this issue, Sweeney and associates from the Texas I Heart Institute [l] propose the use of ”high-risk donor” (HRD) hearts for select critically ill recipients as a strategy to reduce the growing gap between cardiac allograft supply and demand. Their definition of HRD includes one or more of the following variables: age greater than 40 years, noncardiac systemic infections, cardiopulmonary resuscitation longer than 3 minutes, more than 5 hours of graft ischemia, recipient’s weight more than 20% less than the donor‘s weight, and a requirement of more than 10 pg/kg/min of dopamine to maintain hemodynamic stability. Criteria for cardiac allograft donation established by the Stanford group [2] in the early 1970s were used for reference. We agree with Sweeney and associates that the current shortage of donors is the most limiting factor to expansion of heart transplantation. The scarcity of suitable allografts makes the risk of dying while on the waiting list for a heart transplant (20% to 40%) greater than the operative risk or the risk of postoperative complications (10% to 20%) [ 3 ] .

Fluoroscopy and selective angiography of left ventricular assist system inflow cannula as a method of detecting cannula entrapment

Left ventricular assist systems have become an important tool as a bridge to cardiac transplantation. Malfunction of these devices often leads to clinical and hemodynamic deterioration. One potential complication is the obstruction of the inflow cannula secondary to remodeling of the left ventricular cavity. We report two cases where fluoroscopy and selective angiography were used to visualize the orientation and obstruction of the inflow cannula when echocardiographic findings were indeterminant.

Myocardial ultrastructure following prolonged in vitro preservation and heterotopic cardiac transplantation

Abstract Myocardial ultrastructure, using semiquantitative electron microscopy, was compared between two different means of prolonged, in vitro myocardial preservation followed by successful canine, cervical heterotopic cardiac transplantation: (1) 3-hr preservation in 4°C, 158 m M NaCl, (2) 24 hr continuous, low-pressure, nonpulsatile, modified Krebs solution with pretreatment of the donor with Diltiazem (1 mg/kg). All grafts in both groups resumed spontaneous beating after heterotopic allotransplantation and defibrillation. Twenty-four-hour preservation resulted in minimal ultrastructural changes with only mild lightening of the mitochondrial matrix and slight cristae damage. Similar findings were observed 24 hr post-transplantation. In contrast, 3-hr, 4°C, NaCl preservation resulted in focal zones of hypercontraction, clearing of the mitochondrial matrix and cristae damage, and an increase in intracellular lipid deposition which persisted after 24 hr post-transplantation. It is concluded that the continuous perfusion technique may better preserve cellular integrity than current standard preservation modalities in spite of an eightfold increase in total ischemic time.