Rohinton J. Morris

Risk Score Derived from Pre-operative Data Analysis Predicts the Need for Biventricular Mechanical Circulatory Support

BACKGROUND Right ventricular (RV) failure after left ventricular assist device (LVAD) placement is a serious complication and is difficult to predict. In the era of destination therapy and the total artificial heart, predicting post-LVAD RV failure requiring mechanical support is extremely important. METHODS We reviewed patient characteristics, laboratory values and hemodynamic data from 266 patients who underwent LVAD placement at the University of Pennsylvania from April 1995 to June 2007. RESULTS Of 266 LVAD recipients, 99 required RV assist device (BiVAD) placement (37%). We compared 36 parameters between LVAD (n = 167) and BiVAD patients (n = 99) to determine pre-operative risk factors for RV assist device (RVAD) need. By univariate analysis, 23 variables showed statistically significant differences between the two groups (p < or = 0.05). By multivariate logistic regression, cardiac index < or =2.2 liters/min/m(2) (odds ratio [OR] 5.7), RV stroke work index < or =0.25 mm Hg . liter/m(2) (OR 5.1), severe pre-operative RV dysfunction (OR 5.0), pre-operative creatinine > or =1.9 mg/dl (OR 4.8), previous cardiac surgery (OR 4.5) and systolic blood pressure < or =96 mm Hg (OR 2.9) were the best predictors of RVAD need. CONCLUSIONS The most significant predictors for RVAD need were cardiac index, RV stroke work index, severe pre-operative RV dysfunction, creatinine, previous cardiac surgery and systolic blood pressure. Using these data, we constructed an algorithm that can predict which LVAD patients will require RVAD with >80% sensitivity and specificity.

Early planned institution of biventricular mechanical circulatory support results in improved outcomes compared with delayed conversion of a left ventricular assist device to a biventricular assist device

OBJECTIVE It is generally accepted that patients who require biventricular assist device support have poorer outcomes than those requiring isolated left ventricular assist device support. However, it is unknown how the timing of biventricular assist device insertion affects outcomes. We hypothesized that planned biventricular assist device insertion improves survival compared with delayed conversion of left ventricular assist device support to biventricular assist device support. METHODS We reviewed and compared outcomes of 266 patients undergoing left ventricular assist device or biventricular assist device placement at the University of Pennsylvania from April 1995 to June 2007. We subdivided patients receiving biventricular assist devices into planned biventricular assist device (P-BiVAD) and delayed biventricular assist device (D-BiVAD) groups based on the timing of right ventricular assist device insertion. We defined the D-BiVAD group as any failure of isolated left ventricular assist device support. RESULTS Of 266 patients who received left ventricular assist devices, 99 (37%) required biventricular assist device support. We compared preoperative characteristics, successful bridging to transplantation, survival to hospital discharge, and Kaplan-Meier 1-year survival between the P-BiVAD (n = 71) and D-BiVAD (n = 28) groups. Preoperative comparison showed that patients who ultimately require biventricular support have similar preoperative status. Left ventricular assist device (n = 167) outcomes in all categories exceeded both P-BiVAD and D-BiVAD group outcomes. Furthermore, patients in the P-BiVAD group had superior survival to discharge than patients in the D-BiVAD group (51% vs 29%, P < .05). One-year and long-term Kaplan-Meier survival distribution confirmed this finding. There was also a trend toward improved bridging to transplantation in the P-BiVAD (n = 55) versus D-BiVAD (n = 22) groups (65% vs 45%, P = .10). CONCLUSION When patients at high risk for failure of isolated left ventricular assist device support are identified, proceeding directly to biventricular assist device implantation is advised because early institution of biventricular support results in dramatic improvement in survival.

Management of acute cardiac failure with mechanical assist: experience with the ABIOMED BVS 5000

BACKGROUND Mechanical circulatory assist industries have developed ventricular assist devices (VAD) for short-, intermediate-, and long-term use. The purpose of this report is to describe the progress made with the ABIOMED Biventricular System (BVS) 5000 (ABIOMED, Inc, Danvers, MA) short-term VAD. METHODS From June 1994 through August 2000, all cardiogenic shock patients who required short-term mechanical assist were supported with the ABIOMED BVS 5000. Insertion criteria included any condition that may potentially result in cardiac recovery. A formal algorithm for timing of insertion was established to standardize implantation criteria. RESULTS A total of 45 patients were supported at Hahnemann University Hospital, Philadelphia, PA. There were 26 male and 19 female patients, with a mean age of 57.9 years (range 33 to 80 years). Devices were inserted for postcardiotomy shock in 36 patients (80%) and precardiotomy shock in 9 patients (20%). The average duration of support was 8.3 days (range 1 to 31 days). Overall, there were 22 (49%) patients weaned from support and 14 (31%) discharged from the hospital. For patients in whom the device was implanted in accordance with an established protocol (group A), the wean and discharge rates were 60% and 43%, respectively. The most common morbidities included bleeding and adverse neurologic events. CONCLUSIONS The ABIOMED BVS 5000 VAD continues to be a valuable form of short-term mechanical assist for acute cardiogenic shock. The formation of a uniform VAD insertion algorithm has helped to standardize protocols in management.

Limb Ischemia During Femoral Cannulation for Cardiopulmonary Support

OBJECTIVES Extracorporeal membrane oxygenation and extracorporeal cardiopulmonary support (ECMO/CPS) are potentially life-saving techniques for patients with cardiopulmonary collapse. Complications include lower extremity ischemia from femoral artery cannulation. We examined the outcomes of patients placed on ECMO/CPS, including the rate of limb ischemia. METHODS All instances of ECMO/CPS over a 3-year period (2006-2009) at a single university hospital were examined retrospectively for cannulation strategy, perfusion strategy, mortality, and limb ischemia. Potential predictors of limb ischemia with femoral artery cannulation were age, gender, body surface area (BSA), body mass index (BMI), and arterial cannula size. RESULTS Fifty-eight patients were placed on ECMO/CPS. Of these, 43 patients (74%) had femoral arterial cannulation. In 10 patients, the superficial femoral artery (SFA) was cannulated prophylactically (without antecedent limb ischemia) and perfused in the antegrade direction from a branch of the ECMO/CPS circuit. In 7 of the remaining 33 patients (21%), limb ischemia developed requiring decannulation with fasciotomy (n = 4) or additional cannulation of the SFA with branching of the ECMO/CPS circuit (n = 3). One patient with ipsilateral leg ischemia required eventual amputation. Patients with limb ischemia were significantly younger than those who did not develop limb ischemia (P = .001). BSA, BMI, and cannula size did not predict limb ischemia. Overall 30-day mortality following the initiation of ECMO/CPS was 79%. There was no correlation between limb ischemia and mortality. CONCLUSIONS Younger patients may be at increased risk for lower extremity arterial insufficiency with femoral cannulation for ECMO/CPS. Prophylactic or expectant SFA cannulation are reasonable approaches.

Stroke After Aortic Valve Surgery Results From a Prospective Cohort

Background— The incidence and impact of clinical stroke and silent radiographic cerebral infarction complicating open surgical aortic valve replacement (AVR) are poorly characterized. Methods and Results— We performed a prospective cohort study of subjects ≥65 years of age who were undergoing AVR for calcific aortic stenosis. Subjects were evaluated by neurologists preoperatively and postoperatively and underwent postoperative magnetic resonance imaging. Over a 4-year period, 196 subjects were enrolled at 2 sites (mean age, 75.8±6.2 years; 36% women; 6% nonwhite). Clinical strokes were detected in 17%, transient ischemic attack in 2%, and in-hospital mortality was 5%. The frequency of stroke in the Society for Thoracic Surgery database in this cohort was 7%. Most strokes were mild; the median National Institutes of Health Stroke Scale was 3 (interquartile range, 1–9). Clinical stroke was associated with increased length of stay (median, 12 versus 10 days; P=0.02). Moderate or severe stroke (National Institutes of Health Stroke Scale ≥10) occurred in 8 (4%) and was strongly associated with in-hospital mortality (38% versus 4%; P=0.005). Of the 109 stroke-free subjects with postoperative magnetic resonance imaging, silent infarct was identified in 59 (54%). Silent infarct was not associated with in-hospital mortality or increased length of stay. Conclusions— Clinical stroke after AVR was more common than reported previously, more than double for this same cohort in the Society for Thoracic Surgery database, and silent cerebral infarctions were detected in more than half of the patients undergoing AVR. Clinical stroke complicating AVR is associated with increased length of stay and mortality.Background— The incidence and impact of clinical stroke and silent radiographic cerebral infarction complicating open surgical aortic valve replacement (AVR) are poorly characterized. Methods and Results— We performed a prospective cohort study of subjects ≥65 years of age who were undergoing AVR for calcific aortic stenosis. Subjects were evaluated by neurologists preoperatively and postoperatively and underwent postoperative magnetic resonance imaging. Over a 4-year period, 196 subjects were enrolled at 2 sites (mean age, 75.8±6.2 years; 36% women; 6% nonwhite). Clinical strokes were detected in 17%, transient ischemic attack in 2%, and in-hospital mortality was 5%. The frequency of stroke in the Society for Thoracic Surgery database in this cohort was 7%. Most strokes were mild; the median National Institutes of Health Stroke Scale was 3 (interquartile range, 1–9). Clinical stroke was associated with increased length of stay (median, 12 versus 10 days; P =0.02). Moderate or severe stroke (National Institutes of Health Stroke Scale ≥10) occurred in 8 (4%) and was strongly associated with in-hospital mortality (38% versus 4%; P =0.005). Of the 109 stroke-free subjects with postoperative magnetic resonance imaging, silent infarct was identified in 59 (54%). Silent infarct was not associated with in-hospital mortality or increased length of stay. Conclusions— Clinical stroke after AVR was more common than reported previously, more than double for this same cohort in the Society for Thoracic Surgery database, and silent cerebral infarctions were detected in more than half of the patients undergoing AVR. Clinical stroke complicating AVR is associated with increased length of stay and mortality. # CLINICAL PERSPECTIVE {#article-title-47}

Internal thoracic artery for coronary artery grafting in octogenarians

BACKGROUND Use of the left internal thoracic artery as a bypass graft has been shown to result in better long-term patency and improved survival. In elderly patients, the internal thoracic artery has been used less often for coronary artery bypass grafts because of the belief that greater morbidity and mortality are associated with this procedure. This study was undertaken to test this premise in the octogenarian population. METHODS Over an 8-year period, 474 consecutive patients 80 years of age and greater had coronary artery bypass grafting. The left internal thoracic artery was used in 188 patients (39.7%) (group 1) and saphenous vein grafts only (group 2), in 286 (60.3%). The mean age was 82.6 years (range, 80 to 95 years). There were 312 men (65.8%) and 162 women (34.2%). RESULTS Use of the internal thoracic artery as a graft has risen steadily each year, as has the number of patients who are octogenarians. The hospital mortality rate was 7.8%. Patients in group 1 had a mortality rate of 9.0% and patients in group 2, a mortality rate of 7.0%. The mortality rate among survivors at 1 year was 6.7%. Long-term survival was significantly greater in group 1. CONCLUSIONS On the basis of this study, we conclude that the internal thoracic artery is the bypass graft of choice, especially in regard to long-term mortality, and should not be denied to this high-risk group.

Reoperative mitral valve surgery by the port access minithoracotomy approach is safe and effective.

BACKGROUND Reoperative mitral valve (MV) surgery through sternotomy can be technically challenging. Limited exposure and injury to the right ventricle or patent grafts (previous coronary artery bypass graft surgery [CABG]) are potential complications upon sternal reentry. The purpose of this study was to examine the results of port access MV surgery through right minithoracotomy in patients with previous cardiac surgery performed through median sternotomy. METHODS From 1998 through July 2007, 651 port access MV procedures were performed. In 107 patients (16.4%), previous cardiac surgery had been performed through midline sternotomy. Mean age was 67.5 +/- 11.2 years, and 60.7% (n = 65) were male. Previous surgery included CABG (n = 45, 42.1%), aortic valve replacement (n = 9, 8.4%), aortic valve replacement/MV repair (n = 2, 1.9%), MV repair (n = 21, 19.6%), MV replacement (n = 5, 4.7%), CABG/MV replacement (n = 1, 0.9%), CABG/MV repair (n = 8, 7.5%), CABG/aortic valve replacement (n = 2, 1.9%), and others (n = 14, 13.1%). New York Heart Association functional classes were I (n = 2, 1.9%), II (n = 28, 26.2%), III (n = 50, 46.7%), and IV (n = 27, 25.2%). The endoaortic balloon was used in 75 patients (70.1%) and the Chitwood clamp in 11 patients (10.2%). In the remaining patients (n = 21, 19.6%), fibrillatory arrest was employed. RESULTS Mitral valve repair and MV replacement were performed in 60 patients (56.1%) and 47 patients (43.9%), respectively. The 30-day mortality was 4.7% (n = 5). The mean cardiopulmonary bypass and aortic cross-clamp times were 140.8 +/- 43.7 minutes and 77.0 +/- 49.7 minutes, respectively. Complications included 6 reoperations for bleeding (5.6%), 1 stroke (0.9%), and 2 wound infections (1.9%). Conversion to sternotomy was required in 1 patient (0.9%) because of an acute type A dissection secondary to aortic occlusion with Chitwood clamp. The mean hospital stay was 9.6 days. During follow-up, reoperation for failure of MV repair was performed in 4 patients (3.7%). CONCLUSIONS Reoperative port access MV surgery can be performed with minimal morbidity and mortality. This approach may be the preferred technique for patients who require MV procedures after previous cardiac surgery performed through median sternotomy.

Total Artificial Heart—Concepts and Clinical Use

End-stage congestive heart failure remains the leading cause of death in the United States. Despite advances in medical treatment, it also remains the most common reason for admission to the hospital. The gold standard of treatment for the failing heart, orthotopic heart transplantation, is limited by a shortage of donor hearts. There are also a significant number of patients who are not transplant candidates due to comorbid conditions and/or inability to tolerate immunosuppressive therapy. To meet the need for this latter group, the medical field has embraced ventricular assist device (VAD) therapy to extend survival and improve quality-of-life for the end-stage cardiac patient. This therapy, however, has been currently limited to the failing left ventricle and is still fraught with complications that limit long-term and widespread use. The total artificial heart, as currently available with two devices, is rapidly becoming the treatment of choice for biventricular failure.

Coronary Artery Bypass Surgery in Nonagenarians

As the number of nonagenarians increases yearly in the United States, surgeons will be asked more often to evaluate the possibility of intervention for coronary artery disease in this age group. The purpose of this study is to document experience with patients 90 years of age or older in order to determine whether coronary artery bypass grafting surgery is justified. Eleven patients aged 90 years or more underwent cardiac surgery for symptomatic coronary artery disease refractory to medical management between January 1, 1987, and December 31, 1996. All patients were in NYHA Class IV preoper atively. In-hospital death occurred in two patients (18%). In-hospital morbidity occurred in all patients (100%) including seven cardiac, four respiratory, two neurologic, and one infectious. All survivors left the hospital symptomatically improved. The mean length of stay was 28 days. Four patients died at a mean of 2 years and 2 months post operatively. Five patients remain alive at a mean of 1 year and 7 months. Coronary artery bypass grafting in nonagenarians can be performed successfully in selected cases. However, increased mortality and morbidity rates and length of stay are associated with this age group. For survivors, the quality of life is improved and the projected life expectancy restored.

Cardiac retransplantation is an efficacious therapy for primary cardiac allograft failure

BackgroundAlthough orthotopic heart transplantation has been an effective treatment for end-stage heart failure, the incidence of allograft failure has increased, necessitating treatment options. Cardiac retransplantation remains the only viable long-term solution for end-stage cardiac allograft failure. Given the limited number of available donor hearts, the long term results of this treatment option need to be evaluated.Methods709 heart transplants were performed over a 20 year period at our institution. Repeat cardiac transplantation was performed in 15 patients (2.1%). A retrospective analysis was performed to determine the efficacy of cardiac retransplantation. Variables investigated included: 1 yr and 5 yr survival, length of hospitalization, post-operative complications, allograft failure, recipient and donor demographics, renal function, allograft ischemic time, UNOS listing status, blood group, allograft rejection, and hemodynamic function.ResultsEtiology of primary graft failure included transplant arteriopathy (n = 10), acute rejection (n = 3), hyperacute rejection (n = 1), and a post-transplant diagnosis of metastatic melanoma in the donor (n = 1). Mean age at retransplantation was 45.5 ± 9.7 years. 1 and 5 year survival for retransplantation were 86.6% and 71.4% respectively, as compared to 90.9% and 79.1% for primary transplantation. Mean ejection fraction was 67.3 ± 12.2% at a mean follow-up of 32.6 ± 18.5 mos post-retransplant; follow-up biopsy demonstrated either ISHLT grade 1A or 0 rejection (77.5 ± 95.7 mos post-transplant).ConclusionCardiac retransplantation is an efficacious treatment strategy for cardiac allograft failure.