Destination mechanical circulatory support: proposal for clinical standards.
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Assisted Circulation↗
Biomedical subjects
M C Oz
Publications and source records attributed to M C Oz.
The impact of newly diagnosed patent foramen ovale in patients undergoing off-pump coronary artery bypass grafting: case series of eleven patients.
UNLABELLED: The increased use of transesophageal echocardiography (TEE) by anesthesiologists may lead to an increase in the intraoperative detection of previously undiagnosed patent foramen ovale (PFO). The impact of heart manipulation on interatrial shunting through a PFO during off-pump coronary artery bypass graft (CABG) has not been studied. We retrospectively studied 11 patients with PFOs who underwent off-pump CABG. TEE contrast studies and blood gas analyses were performed at baseline, during heart elevation for distal coronary arteries anastomoses, and at the end of the surgery. At baseline, 5 of 11 patients had left-to-right shunting and 2 of 11 had right-to-left shunting. Heart elevation did not result in oxygen desaturation in any patient; however, it caused the disappearance of a right-to-left shunt (n = 1), persistence of this shunt (n = 1), and the development of a new right-to-left shunt (n = 2). Return of the heart to its original position resulted in a return of TEE findings to the baseline state in all patients. This series suggests that off-pump CABG can be performed safely in the majority of patients with PFOs; however, additional investigation is needed to assure that adverse effects do not occur in a subset of patients undergoing off-pump CABG in the presence of a PFO. IMPLICATIONS: This case series suggests that coronary artery bypass graft surgery can be safely performed in most patients with patent foramen ovale without the use of a cardiopulmonary bypass.
Adult↗
Intravenous allicin improves pulmonary blood flow after ischemia-reperfusion injury in rats.
BACKGROUND: Allicin is a sulfur-containing compound extracted from garlic, with antiaggregatory, anti- migratory, anti-oxidant and pulmonary vasodilator actions. We hypothesized that allicin might be beneficial in lung ischemia-reperfusion. METHODS: A non-nothermic rat lung ischemia-reperfusion model was established by clamping left pulmonary artery (PA) for 1 hr, followed by reperfusion for 2 hrs by clamping right PA to reflect solely the function of left lung. Groups were control (n=7), allicin 0.1 mg (n=8) and allicin 0.01 mg (n=4). In the beginning of reperfusion allicin/saline were injected. Pulmonary artery pressures (PAP), pulmonary artery flow (PAF), left atrial pressure (LAP) were monitored. At the end of reperfusion period arterial blood gas (ABG) analysis was done. RESULTS: Six of 7 control and 3 of 8 group 2 animals died before completing the experiment. In group 1 all animals completed the experiment (p=0.015 vs control). PAF was significantly increased after 30, 60 and 120 min of reperfusion in group 1 (p=0.0028, 0.0009, 0.0003 respectively vs control) and after 60 and 120 minutes in group 2 (p=0.0453, 0.018 respectively vs control). Pulmonary vascular resistance was lower at 30 min in allicin 0.01 mg group (p=0.0017 vs control). PAP was increased after 60 and 120 min of reperfusion in group 1 (p=0.016, 0.0029 respectively vs control) and after 120 min in group 2 (p=0.0104 vs control). CONCLUSIONS: This study shows that allicin improves postischemic PAF in this model. Allicin needs further investigation of potential utility and mechanism(s) of action.
Animals↗
Long-term use of a left ventricular assist device for end-stage heart failure.
BACKGROUND: Implantable left ventricular assist devices have benefited patients with end-stage heart failure as a bridge to cardiac transplantation, but their long-term use for the purpose of enhancing survival and the quality of life has not been evaluated. METHODS: We randomly assigned 129 patients with end-stage heart failure who were ineligible for cardiac transplantation to receive a left ventricular assist device (68 patients) or optimal medical management (61). All patients had symptoms of New York Heart Association class IV heart failure. RESULTS: Kaplan-Meier survival analysis showed a reduction of 48 percent in the risk of death from any cause in the group that received left ventricular assist devices as compared with the medical-therapy group (relative risk, 0.52; 95 percent confidence interval, 0.34 to 0.78; P=0.001). The rates of survival at one year were 52 percent in the device group and 25 percent in the medical-therapy group (P=0.002), and the rates at two years were 23 percent and 8 percent (P=0.09), respectively. The frequency of serious adverse events in the device group was 2.35 (95 percent confidence interval, 1.86 to 2.95) times that in the medical-therapy group, with a predominance of infection, bleeding, and malfunction of the device. The quality of life was significantly improved at one year in the device group. CONCLUSIONS: The use of a left ventricular assist device in patients with advanced heart failure resulted in a clinically meaningful survival benefit and an improved quality of life. A left ventricular assist device is an acceptable alternative therapy in selected patients who are not candidates for cardiac transplantation.
Activities of Daily Living↗
Normalized diastolic properties after left ventricular assist result from reverse remodeling of chamber geometry.
BACKGROUND: Normalization of diastolic properties after left ventricular (LV) assist may result from a change in myocardial material properties, chamber size, or both. This study tested the hypothesis that reported normalization of LV diastolic properties is primarily due to remodeling of chamber geometry. METHODS AND RESULTS: Hearts were obtained at transplantation from 8 patients with dilated cardiomyopathy (DCM), 6 patients with DCM plus 33+/-5 days of LV assist, and 3 patients with no evidence of heart failure. LV assist normalized passive pressure-volume curves. Chamber dimensions decreased without a change in the ratio of radius to wall thickness. Midwall stress-stretch relations predicted from pressure-volume and dimension data were not different for DCM and LV assist hearts. Passive stress-stretch relations were measured in endocardial trabeculae and were not different for DCM and LV assist hearts. Myocyte size and collagen area fraction were unchanged at this brief duration of support. CONCLUSIONS: These findings are all consistent with the hypothesis that early normalization of diastolic properties after LV assist device support results from remodeling of chamber geometry, not from changes in tissue stiffness. These data emphasize the importance of geometry to ventricular mechanics and demonstrate that reduction of heart size does not necessarily produce a reduction in wall stress.
Adolescent↗
Comparison of right and left ventricular responses to left ventricular assist device support in patients with severe heart failure: a primary role of mechanical unloading underlying reverse remodeling.
BACKGROUND: Left ventricular assist devices (LVAD) reverse ventricular, myocardial, and systemic abnormalities characteristic of severe heart failure (reverse remodeling). The relative contributions of hemodynamic unloading and normalized biochemical milieu to reverse remodeling are unknown. METHODS AND RESULTS: Structural and functional characteristics were measured from 53 hearts of patients undergoing transplantation without LVAD support (medical support) and 33 hearts from patients receiving a median of 46 days of LVAD support (range, 8 to 360 days). Compared with medical support alone, patients receiving LVAD support for >/=30 days had higher central venous pressures (11+/-6 versus 8+/-5 mm Hg, P=0.04), lower pulmonary artery diastolic pressures (14+/-9 versus 21+/-9 mm Hg, P=0.01), and higher cardiac outputs (5.1+/-1.6 versus 3.7+/-1.0 L/min, P<0.001). In LVAD versus transplantation hearts, V(30) (ex vivo volume yielding ventricular pressure of 30 mm Hg) was decreased in the left ventricle (LV) (179+/-75 versus 261+/-118 mL, P=0.005) but not in the right ventricle (RV) (140+/-59 versus 148+/-52 mL, P=NS). LV myocyte diameter decreased more significantly after LVAD support (17%, P=0.05) than in the RV (11%, P=NS). Compared with transplantation, LVAD support increased normalized SERCA2a content in the LV (0.51+/-0.26 versus 1.04+/-0.34, P<0.001) but not in the RV (0.48+/-34 versus 0.67+/-0.55, P=NS). Finally, LVAD support improved force-frequency relations of isolated superfused LV trabeculae (P=0.01) but not RV trabeculae. CONCLUSIONS: Reduction of hemodynamic load is a primary factor underlying several important features of reverse remodeling. These findings do not preclude a possible primary role of neurohormonal factors underlying other facets of reverse remodeling during LVAD support.
Adult↗
Pretransplant cachexia and morbid obesity are predictors of increased mortality after heart transplantation.
BACKGROUND: Extremes in body weight are a relative contraindication to cardiac transplantation. METHODS: We retrospectively reviewed 474 consecutive adult patients (377 male, 97 female, mean age 50.3+/-12.2 years), who received 444 primary and 30 heart retransplants between January of 1992 and January of 1999. Of these, 68 cachectic (body mass index [BMI]<20 kg/m2), 113 overweight (BMI=>27-30 kg/m2), and 55 morbidly obese (BMI>30 kg/m2) patients were compared with 238 normal-weight recipients (BMI=20-27 kg/m2). We evaluated the influence of pretransplant BMI on morbidity and mortality after cardiac transplantation. Kaplan-Meier survival distribution and Cox proportional hazards model were used for statistical analyses. RESULTS: Morbidly obese as well as cachectic recipients demonstrated nearly twice the 5-year mortality of normal-weight or overweight recipients (53% vs. 27%, respectively, P=0.001). An increase in mortality was seen at 30 days for morbidly obese and cachectic recipients (12.7% and 17.7%, respectively) versus a 30-day mortality rate of 7.6% in normal-weight recipients. Morbidly obese recipients experienced a shorter time to high-grade acute rejection (P=0.004) as well as an increased annual high-grade rejection frequency when compared with normal-weight recipients (P=0.001). By multivariable analysis, the incidence of transplant-related coronary artery disease (TCAD) was not increased in morbidly obese patients but cachectic patients had a significantly lower incidence of TCAD (P=0.05). Cachectic patients receiving oversized donor hearts had a significantly higher postoperative mortality (P=0.02). CONCLUSIONS: The risks of cardiac transplantation are increased in both morbidly obese and cachectic patients compared with normal-weight recipients. However, the results of cardiac transplantation in overweight patients is comparable to that in normal-weight patients. Recipient size should be kept in mind while selecting patients and the use of oversized donors in cachectic recipients should be avoided.
Adult↗
Mechanical cardiac support 2000: current applications and future trial design: June 15-16, 2000 Bethesda, Maryland.
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Clinical Trials as Topic↗
Fungal left ventricular assist device endocarditis.
BACKGROUND: Infection remains as the most serious complication and represents a significant threat to patients during long-term mechanical circulatory support. Fungal infection is a particularly worrisome complication and left ventricular assist device (LVAD) endocarditis does pose a serious threat. METHODS: One hundred and sixty-five patients underwent TCI Heartmate LVAD implantation between July 1991 and December 1999 at our institution. Detailed medical records were kept prospectively for all patients, and a variety of infection-related endpoints were analyzed on patients with fungal LVAD endocarditis. RESULTS: Thirty-seven patients (22%) developed fungal infections during LVAD support. Five (3%) of those met our criteria for the diagnosis of fungal LVAD endocarditis. Microbial portals of entry were identifiable in all cases. Infections were managed successfully in 4 patients (80%). CONCLUSIONS: The successful management of fungal LVAD endocarditis currently requires early recognition of potentially nonspecific signs and symptoms, and timely institution of antifungal therapy. In some cases with device-specific manifestations of LVAD endocarditis, device removal and replacement is necessary. In patients with clinical manifestations of sepsis and fungal driveline site or pocket infections without positive blood culture, urgent transplantation may be the appropriate management. In the setting of shortage in the donor supply, device removal and replacement is necessary.
Amphotericin B↗
Passive ventricular constraint for the treatment of congestive heart failure.
Progressive heart failure is characterized by loss of cardiac function associated with maladaptive changes in myocardial gene expression and neuroendocrine activity, leading to progressive increases in heart size. Elevated ventricular wall stress results from an increase in chamber size, and is thought to play a role in furthering development towards end-stage disease. Reduction of wall stress and stress mediated myocardial stretch may be an important means for mitigating heart failure progression. One possible approach to accomplish this goal is through passive support of the heart with the Cardiac Support Device. Results from preclinical and clinical evaluation give support to this premise.
Cardiomyopathy, Dilated↗
Indications and patient selection for mechanical ventricular assistance.
Cardiac assist devices have become an important component of transplantation programs as they successfully bridge unsalvageable patients who would otherwise die. The indications for a device can still be classified into short-term and long-term situations. The short-term indications have expanded into areas such as postcardiotomy failure, high-risk cardiac operations, and acute myocardial infarction with results that were not previously possible in the absence of a well-established mechanical assistance program. Appropriate patient selection remains challenging and perhaps the most important attribute of a successful ventricular assist program. Although few exact criteria can define patients who are not eligible, several considerations and screening scales can help determine a particular patient's suitability. Specific attention must be given to right heart function, neurologic status, existing infections, renal function, and transplantation suitability. The future of this field will not only be in technological advances with devices but in optimization of patient selection and expanding indications such as permanent replacement therapy.
Algorithms↗
Optimal timing of revascularization: transmural versus nontransmural acute myocardial infarction.
BACKGROUND: Higher mortality for emergency coronary artery bypass grafting (CABG) after an acute myocardial infarction (AMI) is well established. Whether it applies to both transmural and nontransmural AMI is unclear. This information may have different therapeutic implications for each cohort of patients. METHODS: A retrospective multicenter analysis of 44,365 patients who underwent CABG after myocardial infarction between 1993 and 1996 by 179 surgeons at 32 hospitals in New York State was performed. RESULTS: Overall hospital mortality for all patients with or without AMI was 2.5% versus 3.1% for patients who underwent CABG with history of myocardial infarction. Hospital mortality decreased with increasing time interval between CABG and AMI; 11.8%, 9.5%, and 2.8% (p < 0.001 for all values) for less than 6 hours, 6 hours to 1 day, and greater than 1 day, respectively. Patients with transmural and nontransmural AMI had identical mortality of 3.1%. However, different patterns emerged when comparing these two groups of patients with respect to time of operation. Mortality was higher in the transmural group if CABG was performed within 7 days after AMI. Multivariate analysis confirmed that CABG within 1 day and 6 hours of AMI are independent risk factors for mortality in the transmural and nontransmural groups, respectively. CONCLUSIONS: Early operation after transmural AMI has a significantly higher risk, and surgeons should be prepared to provide aggressive cardiac support including left ventricular assist devices in this ailing population. Waiting in some may be warranted.
Adult↗
A new off-pump technique for thoratec right ventricular assist device insertion.
The need for right ventricular support as an adjunct to left ventricular assistance is uncommon. When required, the insertion of a right ventricular assist device may be complicated by preexisting hepatic dysfunction, coagulation abnormalities, and renal failure, all of which are exacerbated by cardiopulmonary bypass. We report a technique for insertion of a right ventricular assist device without the need for cardiopulmonary bypass.
Cardiomyopathies↗
Surgical management of valvular disease in patients requiring left ventricular assist device support.
BACKGROUND: Success with long-term implantable left ventricular assist devices (LVAD) has led to increased use in patients previously thought to be unsuitable for mechanical circulatory assistance. Patients with preexisting or newly diagnosed valvular disease have been traditionally excluded from device placement. The purpose of this study was to review our experience with LVAD support in patients with valvular disease and to develop a management algorithm for these difficult patients. METHODS: We reviewed the clinical records of 199 consecutive patients who received the ThermoCardiosystems, Inc, HeartMate Pneumatic or Vented Electric LVAD. There were 18 patients (9%) who required surgical management of native or prosthetic valvular disease during LVAD implantation. RESULTS: Suture or patch closure of the aortic valve was performed in 6 patients, aortic valve plication and repair in 1 patient, mitral valve repair in 4 patients, and tricuspid valve annuloplasty in 5 patients. Two patients with mechanical mitral valve prostheses were treated with postoperative warfarin anticoagulation. Fifteen of the 18 patients with valvular pathology survived the immediate postoperative period (17% mortality). Eleven patients have either undergone transplantation or continue to be supported with an LVAD (61%). Operative mortality in LVAD patients without concomitant valve repair was 18% (n = 33) with a late mortality of 7% (n = 13). Seven of these late deaths occurred in patients who received a device as destination therapy. In the remaining 6 patients, the cause of death was sepsis (n = 2), multisystem organ failure (n = 2), driveline rupture (n = 1), and massive gastrointestinal bleed (n = 1). CONCLUSIONS: Preexisting native or prosthetic valve pathology does not increase the immediate perioperative risk of LVAD insertion; however, these patients continue to pose a challenge for postoperative management while awaiting transplantation.
Adult↗
Surgical treatment of atrial fibrillation using radiofrequency energy.
BACKGROUND: The Maze III procedure for atrial fibrillation (AF) is effective but has not been used widely due to its complexity, bleeding risk, and added operative time. Surgical radiofrequency ablation may simplify the procedure and make intraoperative correction of AF more accessible and widely performed. METHODS: Endocardial pulmonary venous isolation was performed on 48 patients with AF undergoing concurrent operation using temperature-controlled radiofrequency energy delivered through a hand-held flexible probe. Additional right-sided lesions were made at the surgeon's discretion. RESULTS: Forty-two patients were appropriate for analysis (6 died). These patients had an AF duration of 4.8 +/- 6.4 years. At a mean follow-up of 138 +/- 96 days, 34 patients were in sinus rhythm. We were unable to demonstrate a difference in outcome based on AF duration, left atrial size, or addition of right-sided lesions. CONCLUSIONS: Radiofrequency atrial ablation was effective in 81% of patients with AF at restoring sinus rhythm at an average follow-up of 4 months. This procedure is simple to perform and should broaden the number of patients that receive an AF treatment procedure during concurrent cardiac operation.
Adult↗
Long-term outcomes after cardiac transplantation: an experience based on different eras of immunosuppressive therapy.
BACKGROUND: Constantly changing practices in heart transplantation have improved posttransplant survival in patients with end-stage heart disease. The objective of this study was to evaluate long-term outcomes in different eras of immunosuppressive therapy after cardiac transplantation at a single center during a two-decade period. METHODS: A retrospective review of 1,086 consecutive cardiac allograft recipients who underwent transplantation between 1977 to 1999 was performed. Patients were divided into four eras based on type of immunosuppressive therapy: era 1 = steroids, azathioprine (n = 26, February 1977 to March 1983), era II = steroids, cyclosporine (n = 43, April 1983 to April 1985), era III = cyclosporine, steroids, azathioprine (n = 752, April 1985 to December 1995), era IV = cyclosporine, steroids, mycophenolate mofetil (n = 315, January 1996 to October 1999). RESULTS: The actuarial survival of the entire cohort of 1,086 patients undergoing cardiac transplantation was 79%, 66%, and 49% at 1, 5, and 10 years, respectively. There were significant trends in recipient age and gender distribution among the four eras with increasing proportion of older age (> 60 years) and female recipients in eras III and IV (p = 0.001 and 0.02). Early mortality and long-term survival improved significantly over all eras (p < 0.001). Rejection as a cause of death decreased over time (era I, 24%; era II, 21%; era III, 15%; era IV, 9%; p = 0.02), whereas the contribution of transplant coronary artery disease as a cause of death remained unchanged. CONCLUSIONS: Cardiac transplantation provides satisfactory long-term survival for patients with end-stage heart failure. The improving outcomes in survival correlate with improved immunosuppressive therapy in each era. Although the reasons for improvement in survival over time are multifactorial, we believe that changes in immunosuppressive therapy have had a major impact on survival as evidenced by the decreasing number of deaths due to rejection.
Actuarial Analysis↗
Novel technique to repair type A acute aortic dissection in patients with a left ventricular assist device.
Acute type A aortic dissection is an uncommon complication with left ventricular assist device insertion, but is often fatal even if successfully repaired with conventional techniques including aortic valve repair. Residual aortic insufficiency is common because this valve is now subjected to systolic pressure. We present a novel technique for the repair of type A acute aortic dissection in patients with a left ventricular assist device with no chance of residual aortic insufficiency.
Aged↗
Factors affecting long-term survival (>10 years) after cardiac transplantation in the cyclosporine era.
OBJECTIVES: The aim of this study was to determine long-term survival (>10 years) after cardiac transplantation in the cyclosporine era and identify risk factors influencing long-term survival. BACKGROUND: Despite the availability of newer modalities for heart failure, cardiac transplantation remains the treatment of choice for end-stage heart disease. METHODS: Between 1983 and 1988, 195 patients underwent heart transplantation at a single center for the treatment of end-stage heart disease. Multivariable logistic regression analysis of pretransplant risk factors affecting long-term survival after cardiac transplantation included various recipient and donor demographic, immunologic and peritransplant variables. RESULTS: Among the group of 195 cardiac transplant recipients, actuarial survival was 72%, 58% and 39% at 1, 5 and 10 years respectively. In the 65 patients who survived >10 years, mean cardiac index was 2.91/m2 and mean ejection fraction was 58%. Transplant-related coronary artery disease (TRCAD) was detected in only 14 of the 65 patients (22%). By multivariable analysis, the only risk factor found to adversely affect long-term survival was a pretransplant diagnosis of ischemic cardiomyopathy (p = 0.04). CONCLUSIONS: Long-term survivors maintain normal hemodynamic function of their allografts with a low prevalence of TRCAD. It is possible that similar risk factors that lead to coronary artery disease in native vessels continue to operate in the post-transplant period, thereby contributing to adverse outcomes after cardiac transplantation. Aggressive preventive and therapeutic measures are essential to limit the risk factors for development of coronary atherosclerosis and enable long-term survival after cardiac transplantation.
Adolescent↗