Nelson A. Burton

Postoperative complications among octogenarians after cardiovascular surgery

BACKGROUND The octogenarian patient is often perceived as too fragile to undergo cardiothoracic surgery. Our study aimed to compare postoperative complications in patients aged less than 80 versus elderly patients (80 years or more) after surgical cardiac intervention (coronary artery bypass or valve replacement). METHODS Subjects were all patients (n = 8,361) who had an open-heart procedure, either coronary artery bypass or valve implantation or replacement, at two medical centers located in northern Virginia using the same surgical group. A computerized medical record database was reviewed to determine preoperative risk factors and postoperative outcomes. Predictors of complications were identified by univariate and multivariate logistic regression. RESULTS A total of 3,214 complications were recorded. The most prevalent complications were prolonged ventilation time in the intensive care unit, reoperation for bleeding, and pneumonia. The overall mortality rate was 2.4% (204 of 8,361). Persons aged over 80 years had nearly double the mortality rate compared with younger patients (4.1% [18 of 444] to 2.3% [186 of 7,917]). Age greater than 80 years (odds ratio = 2.65, 95% confidence interval = 2.18 to 3.22) and male gender (odds ratio = 0.62, 95% confidence interval = 0.56 to 0.69) were the best univariate predictors of a single postoperative complication. CONCLUSIONS Octogenarian patients manifested twice the risk of death from a cardiac intervention with an average 2-day longer hospital stay compared with their younger counterparts. Furthermore, octogenarians were at markedly higher risk of nonfatal postoperative complications.

A reliable bridge to cardiac transplantation: The TCI left ventricular assist device

The Thermo Cardiosystems (TCI) HeartMate, a pneumatically driven, implantable left ventricular assist device, was designed for long-term support of the failing heart. Between February 1990 and August 1992, the HeartMate was implanted in 11 heart transplant candidates because of profound deterioration of left ventricular function. Patients had a mean cardiac index of 1.6 L.min-1 x m-2 and a mean pulmonary capillary wedge pressure of 33 mm Hg despite maximal pharmacologic support with at least three inotropic medications. In addition, 5 patients were being supported with an intraaortic balloon pump. Nine patients were bridged successfully to cardiac transplantation. The mean cardiac index after implantation of the left ventricular assist device was 3.2 L.min-1 x m-2. Support ranged from 2 to 143 days (mean duration, 60 days). One patient died early of low output secondary to right heart failure, and a second died of air embolism, which occurred intraoperatively. All surviving patients became fully ambulatory. There were no thromboembolic complications during a total of 658 patient-days of support on a regimen of only 80 mg of aspirin daily. The 9 bridged patients are currently alive 4 to 34 months after transplantation. The TCI HeartMate provides safe and effective hemodynamic support with low risk of complications and virtual freedom from thromboembolism on a regimen of minimal anticoagulation.

Aortic cannula velocimetry

Robert C Groom, Aaron G Hill The Virginia Heart Center at Fairfax Hospital, Falls Church, Virginia, Barry Kuban The Ohio State University Department of Biomedical Engineering, Columbus, Ohio, William Oneill 3M Cardiovascular, Incorporated, Ann Arbor, Michigan, Bechara F Akl, Alan M Speir, James Koningsberg, Gregory T Sprissler, Mohamed Shakoor, Paul S Massimiano, Nelson A Burton, Robert A Albus, Quentin Macmanus and Edward A Lefrak The Virginia Heart Center

The use of percutaneous ECMO support as a 'bridge to bridge' in heart failure patients: a case report.

A 65-year-old male with a known history of ischemic cardiomyopathy was admitted to the intensive care unit in cardiogenic shock. Cardiac catheterization revealed bi-ventricular hypokinesis, with an estimated ejection fraction of 15%. Despite moderate inotropic support, the patient’s liver enzymes, international normalization ratio (INR), and creatinine became grossly elevated, indicating multi-organ injury from hypoperfusion. Due to the patient’s state of shock and probable bleeding complications, a full sternotomy and emergent biventricular assist device insertion was deemed very high risk. In order to achieve hemodynamic stability, a decision was made for extracorporeal membrane oxygenation (ECMO) support. ECMO support was quickly initiated by percutaneous cannulation of the femoral vein and artery. The ECMO circuit was comprised of a Centrimag blood pump and Quadrox-D Safeline-coated membrane oxygenator. With successful perfusion and organ resuscitation, abnormal liver function tests, INR, and creatinine all returned to normal in less than one week. With normal organ function, especially the liver, the patient successfully underwent an implantable left ventricular assist device, HeartMate II LVAD, without requiring mechanical right heart support. Prior to ECMO, the patient was at very high risk of needing biventricular support. Thus, the temporary use of ECMO allowed for a safer and more durable bridge to transplantation. The use of percutaneous ECMO has many advantages, including improving the patient condition and allowing for time to evaluate fully the LVAD patient.

Results of myocardial revascularization in black males

The impact of black-white differences in the prevalence of risk factors for coronary heart disease on the outcome of coronary bypass surgery has not been well defined. Preoperative status, coronary anatomy, and surgical results were reviewed in 54 black males operated on between December 1970 and August 1983. With the use of criteria established by the New York Heart Association, five patients were classified in class II, 34 were in class III, and 15 were in class IV. Five patients had unstable angina. The most common risk factor, cigarette smoking, occurred in 43 patients (80%). Thirty patients (56%) had hypertension, 10 (19%) were diabetic, 14 (26%) were obese, and 23 (43%) had a family history of coronary disease. Elevated cholesterol and triglyceride levels were present in 8 and 12 patients, respectively. An average of 2.9 grafts per patient was placed. Overall operative mortality was 5.6%. Prior to the use of cardioplegia in 1978, there were two deaths among 14 patients (mortality, 14%). Since 1978 there has been one death among 40 patients (mortality, 2.5%). Although immediate operative mortality appears not to be affected by black-white status, long-term prognosis may be influenced significantly by the high prevalence of hypertension and diabetes and the lower prevalence of hyperlipidemia among black patients.

Effect of patient age on blood product transfusion after cardiac surgery.

OBJECTIVE Blood product transfusion after cardiac surgery is associated with increased morbidity and mortality. Transfusion thresholds are often lower for the elderly, despite the lack of clinical evidence for this practice. This study examined the role of age as a predictor for blood transfusion. METHODS A total of 1898 patients were identified who had nonemergent cardiac surgery, between January 2007 and August 2013, without intra-aortic balloon pumps or reoperations, and with short (<24 hours) intensive care unit stays (age ≥75 years; n = 239). Patients age ≥75 years were propensity-score matched to those age <75 years to balance covariates, resulting in 222 patients per group. Analyses of the matched sample examined age as a continuous variable, scaled in 5-year increments. RESULTS After matching, covariates were balanced between older and younger patients. Older age significantly predicted postoperative (odds ratio = 1.39, P = .028), but not intraoperative (odds ratio = 0.96, P = .559), blood transfusion. Older age predicted longer length of stay (B = 0.21, P < .001), even after adjustment for blood product transfusion (B = 0.20, P < .001). As expected, older age was a significant predictor for poorer survival, even with multivariate adjustment (hazard ratio = 1.34, P = .042). CONCLUSIONS In patients with a routine postoperative course, older age was associated with more postoperative blood transfusion. Older age was also predictive of longer length of stay and poorer survival, even after accounting for clinical factors. Continued study into effects of transfusion, particularly in the elderly, should be directed toward hospital transfusion protocols to optimize perioperative care.

Cardiac Assist Devices

The two primary goals of mechanical circulatory support are to provide adequate perfusion of the vital organs and to decrease cardiac work. The support of the myocardium is in an effort to cause a reversal of cardiac damage. The recovery process apparently takes place in two stages. Initially, there is a rapid functional recovery of cells in marginally ischemia areas. Then there is a slower process of hypertrophy of normal and recovering myofibers. The process involves the reversal of interstitial and of intercellular myocardial edema in areas of viable myocardium while halting the extension of necrosis into reversibly ischemic areas. It appears that this process is extended from 3 to 5 days, and functional recovery can occur for up to 2 weeks. After a 2-week period, there appears to be little functional recovery of myocardial cells. In autopsy series of nonsurvivors, it appears that most of the patients had suffered from biventricular failure. Biventricular failure appears to be one of the more common complications of the support patient. Right ventricular failure will be attempted to be supported by right ventricular assist devices. The right ventricular assist device, unfortunately, adds a level of complication to the recovery process for the bridge-to-transplant or cardiomyopathy patient. The patients who are involved in support fall into three categories: (1) the bridge-to-transplant patient, (2) the patient recovering from postcardiotomy, and (3) the patient who recovers from an acute myocardial insult. It appears that after 2 weeks the recovery period for all of these groups demonstrates no further functional recovery. The bridge-to-transplant patients usually need to be supported until the transplant occurs. The postcardiotomy patient and the acute myocardial failure patient are the most disappointing support group, since they have a higher morbidity and mortality, and a lower chance of recovery. Salvage rates appear to be in approximately the 25% range in the acute insult category.

THE PERFORMANCE OF THE EUROSCORE AND THE SOCIETY OF THORACIC SURGEONS MORTALITY RISK SCORE: THE GENDER FACTOR

The purpose of this study was to explore potential differences in the performance of the EuroSCORE and the STS mortality risk score in the prediction of operative mortality following cardiac surgery with special focus on the impact of gender. We retrospectively reviewed 3125 consecutive cases of coronary artery bypass surgery performed at our institution between 2001 and 2004. STS and EuroSCORE (logistic [E-log] and additive [E-add]) operative mortality risk scores were calculated for each patient and stratified by gender (female: n=692; male: n=2433). Mortality risk scores were compared between the STS and EuroSCORE using C-statistics and likelihood ratios (LR). Stratified by gender, the E-log and E-add correlated well with the STS (female: r=0.77, 0.78, P<0.001; male: r=0.78, 0.79, P<0.001). Using C-statistics generated from logistic regression, both EuroSCORE models correctly modeled operative mortality compared to the STS. Among male patients, the EuroSCORE C-statistic (E-log, 0.808; E-add, 0.809; STS, 0.796) performed more comparable to the STS than female patients (E-log, 0.853; E-add, 0.855; STS, 0.827). Our results suggest that both the STS risk scores and the EuroSCORE are good predictors for operative mortality with slight advantage for the STS risk score. Combined with the ease of use, we conclude that the EuroSCORE is another viable, bedside instrument for surgeons looking for a preoperative assessment of mortality risk, particularly in female patients undergoing cardiac surgery.