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Biomedical subjects

Ram Sharony

Publications and source records attributed to Ram Sharony.

28 records · Page 2Linked to original sources
PubMed2003

Aortic valve replacement in patients with impaired ventricular function.

BACKGROUND: Patients with reduced ventricular function undergoing aortic valve replacement have increased operative risks, but the impact of valvular pathophysiology and other risk factors has not been clearly defined. METHODS: From June 1992 through June 2002, 1,402 consecutive patients underwent isolated aortic valve surgery with or without coronary artery bypass grafting; of these patients, 416 had an ejection fraction less than 40% and are the subject of this report. These patients (mean age, 68.6) had severe stenosis (62.5%), severe regurgitation (30.3%), or mixed disease (7.2%). Aortic valve replacement plus coronary artery bypass grafting was performed in 48.4% of patients, and 27% had previous cardiac surgery. Follow-up included echocardiography and survival analysis. RESULTS: Hospital mortality was 10.1% (42 of 416), with no difference between aortic stenosis (9.6%) and regurgitation (11.1%). Multivariate analysis revealed that age (p = 0.002) and renal disease (odds ratio = 4.2; 95% confidence interval, 1.9 to 9.3; p = 0.001) were independently associated predictors of mortality. Valvular pathophysiology had no impact on mortality. Peripheral vascular disease, multivessel coronary disease, and renal disease were associated risks for any postoperative complication. Peripheral vascular disease (odds ratio = 12.3, p = 0.02), history of cerebrovascular disease (odds ratio = 4.8, p = 0.038), and diabetes (odds ratio = 2.7, p = 0.04) were associated risks for stroke. The ejection fraction was more than 40% in 52% of the patients who had postoperative echocardiography (mean follow-up, 6 months). Actuarial survival revealed no difference between pathophysiologic groups. CONCLUSIONS: Aortic valve surgery in patients with impaired ventricular function carries an acceptable operative risk that can be stratified by age and comorbidities. The type of valvular pathophysiology does not significantly affect mortality.

Aged↗
PubMed2003

Activation of mitogen-activated protein kinases during preparation of vein grafts and modulation by a synthetic inhibitor.

OBJECTIVE: Long-term durability of saphenous vein grafts used for coronary artery bypass grafting is limited by neointimal formation. Arterial vascular injury is known to activate intracellular mitogen-activated protein kinases, including extracellular signal-regulated kinases and c-jun N-terminal kinases, that affect cell differentiation, proliferation, migration, and apoptosis. This study tests the hypothesis that these mitogen-activated protein kinases are activated in saphenous veins during preparation for coronary artery bypass grafting. METHODS: Saphenous veins were harvested from 10 patients undergoing coronary artery bypass grafting. A specimen from each vein was placed in ice-cold lysis buffer immediately after harvesting (t = 0). The remaining tissue was incubated at room temperature in normal saline, 0.1% dimethylsulfoxide (vehicle), or 50 mmol/L PD98059 (mitogen-activated protein kinase kinase-1/2 inhibitor) until the vein was grafted (mean 50 minutes). To study kinetics of intracellular signaling pathways, canine saphenous veins were harvested, and mitogen-activated protein kinases and PI-3 kinase pathways were studied after different incubation time intervals. Extracted proteins were analyzed by Western blotting or in vitro kinase assay. RESULTS: The human saphenous veins showed elevated levels of active extracellular signal-regulated kinase after harvesting (t = 0) and prior to implant (t = 1). Incubation with PD98059 resulted in decreased activation of extracellular signal-regulated kinase. Kinetics of canine saphenous veins showed extracellular signal-regulated kinase and c-jun N-terminal kinase activation, in a time-dependent manner, along with activation of the growth factor-regulated PI3 kinase pathway. CONCLUSIONS: This study characterizes activation of extracellular signal-regulated kinases and c-jun N-terminal kinases during vein graft preparation and demonstrates the ability to inhibit extracellular signal-regulated kinase activation by simple incubation with a specific inhibitor. Further studies are needed to evaluate the significance of these findings with respect to graft durability.

Animals↗
PubMed2003

Routine intraoperative transesophageal echocardiography identifies patients with atheromatous aortas: impact on "off-pump" coronary artery bypass and perioperative stroke.

BACKGROUND: Patients with severe atheromatous aortic disease (AAD) undergoing coronary artery bypass grafting (CABG) have increased operative risks. The "off-pump" CABG (OPCAB) technique was evaluated in patients given the diagnosis of severe AAD by routine transesophageal echocardiography. METHODS: A total of 5737 patients underwent CABG, with 913 having transesophageal echocardiography findings of severe AAD. Of the patients with severe AAD, 678 (74.3%) had conventional CABG and 235 (25.7%) had OPCAB. RESULTS: Hospital mortality was 8.7% for conventional CABG and 5.1% for OPCAB (P =.08). Multivariate analysis revealed that increased mortality was significantly associated with acute myocardial infarction, conventional CABG, age, renal disease, history of stroke, and ejection fraction < 30%. Neurologic complications occurred in 6.3% of patients undergoing CABG and in 2.1% undergoing OPCAB (P =.01). Freedom from any complication was significantly greater with OPCAB. CONCLUSION: Routine intraoperative transesophageal echocardiography identifies patients with severe AAD. In these patients, OPCAB technique is associated with a lower risk of death, stroke, and all complications.

Aged↗
PubMed2003

Strict thermoregulation attenuates myocardial injury during coronary artery bypass graft surgery as reflected by reduced levels of cardiac-specific troponin I.

We assessed the cardioprotective effects of perioperative maintenance of normothermia by determining the perioperative profile of troponin I, a highly cardiac-specific protein important in risk stratification of patients with acute ischemic events. Candidates for their primary coronary artery bypass grafting (CABG) were randomized into a new thermoregulation system group, Allon( thermoregulation (AT; n = 30), and a routine thermal care (RTC; n = 30) group. Anesthetic and operative techniques were similar in both groups. Intraoperative warming was applied before and after cardiopulmonary bypass (CPB) and up to 4 h after surgery. Perioperative temperature and hemodynamic data were recorded. Blood samples for creatine kinase (CK) and its isoform, MB (CK-MB), and for cardiac-specific troponin I (cTnI) were obtained at predetermined intervals throughout the entire operation. Core and skin temperatures were higher in the AT group at all time points. The systemic vascular resistance was lower and the cardiac index higher in the AT group at all intra- and postoperative time points. Increases in CK, CK-MB, and cTnI levels indicated intraoperative ischemic insult in all patients. The respective CK levels for the AT and RTC groups were 53.3 +/- 22.7 IU/L and 47.9 +/- 17.86 IU/L at the time of anesthesia and 64.7 +/- 45.6 IU/L and 47.8 +/- 19.4 IU/L 30 min after the onset of surgery, demonstrating thereafter a steep increase before the discontinuation of CPB. CK-MB mass concentrations in both groups behaved almost identically. Pre-CPB cTnI levels at anesthesia induction were 0.3 +/- 0 ng/mL in both groups, followed by a distinctive profile observed after separation from CPB: 28.1 +/- 11.4 ng/mL, 26.05 +/- 9.20 ng/mL, and 22.3 +/- 8.9 ng/mL at discontinuation from CPB, chest closure, and 2 h after surgery, respectively, in the RTC group, versus 0.6 +/- 4.6 ng/mL, 6.6 +/- 5.5 ng/mL, and 7.9 +/- 4.76 ng/mL at these three time points, respectively, in the AT group (P < 0.01 between groups at the specified time points). Contrary to conventional thinking about the benefits of hypothermia, maintenance of normothermia throughout the non-CPB phases during CABG was demonstrated to be important in attenuating myocardial ischemic injury. Insofar as troponin I was more sensitive than other tested markers, it may provide important data on possible protection from myocardial insult and on other cardioprotective measures.

Aged↗
PubMed2002

Right heart support during off-pump coronary artery bypass surgery--a multi-center study.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) surgery for posterior and inferior wall vessels requires heart displacement, which leads to hemodynamic instability. Based on results indicating that displacement primarily alters right heart function, this study evaluates the safety and efficacy of right heart support during OPCAB surgery to the posterior and inferior wall vessels. METHODS: In a multi-center, prospective study, 25 patients underwent multi-vessel OPCAB surgery. Right heart support was carried out using the Enabler circulatory support system (Hemodynamics Systems Ltd., Upper Yokneam, Israel). Hemodynamic measurements were recorded at baseline and during heart displacement with and without right heart support. RESULTS: No mortality was recorded. Mean graft number was 2.25 +/- 0.36. Inability to position the Enabler system occurred in five cases. Once the Enabler was properly positioned, there was no case of conversion to cardiopulmonary bypass (CPB) due to failure of the Enabler to provide adequate support. Cardiac index (CI) declined from 2.4 +/- 0.5 L/min x /m2 to 1.6 +/- 0.6 L/min x /m2 (p <0.05) during heart displacement and increased to 2.3 +/- 0.6 L/min x /m2 (p <0.05) following Enabler activation. Mean arterial blood pressure (MAP) dropped from 82 +/- 18.6 mmHg to 53.1 +/- 16.6 mmHg (p <0.001) during heart displacement and was restored to 69.8 +/- 19.4 mmHg (p <0.001) with Enabler support. CONCLUSIONS: Heart displacement caused a significant hemodynamic deterioration that was stabilized with right heart support. The Enabler system is safe and effective in facilitating multi-vessel OPCAB surgery. However, there are still serious technical problems during cannula insertion that cause an unacceptable failure rate of device utilization.

Aged↗
PubMed2002

A new thermoregulation system for maintaining perioperative normothermia and attenuating myocardial injury in off-pump coronary artery bypass surgery.

BACKGROUND: Most patients undergoing coronary artery bypass surgery demonstrate perioperative mild-to-moderate hypothermia (<36 degrees C). Patients undergoing off-pump coronary artery bypass (OPCAB) grafting may become even more severely hypothermic for want of cardiopulmonary bypass rewarming. One consequence is increased circulating catecholamine levels that induce an elevated systemic vascular resistance (SVR), which causes a subsequent deterioration in cardiac output. MATERIALS AND METHODS: We assessed the ability of the Allon thermoregulatory (AT) system to maintain normothermia and its impact on hemodynamics and myocardial function in patients undergoing OPCAB surgery. In this study, the first 60 of 120 suitable patients were assigned to AT (n = 40) or routine thermal care (RTC) (n = 20). Core body temperature, cardiac index (CI), SVR, and cardiac-specific troponin I (cTnI) were analyzed perioperatively for patients in both groups. RESULTS: Core body temperature was significantly higher in the AT group (from 36.1 degrees C +/- 0.5 degrees C at induction of anesthesia to 37 degrees C +/- 0.5 degrees C during surgery) than in the RTC group (from 35.8 degrees C +/- 0.4 degrees C to 35.2 degrees C +/- 0.8 degrees C, respectively; P <.01). SVR was significantly lower, and CI was greater (at comparable time points), whereas cTnI levels in the AT group were lower than in the RTC group from the end of surgery until 24 hours postoperatively (7.4 +/- 17.7 g/L versus 31.9 +/- 47.4 g/L; P =.03). These findings indicate the possibility for less ischemic damage sustained intraoperatively in the AT group. CONCLUSIONS: Maintenance of perioperative normothermia (36.5 degrees C-37.5 degrees C) during OPCAB procedures can be efficiently achieved with the Allon thermoregulation system. The system was found to be superior to other routinely used methods of temperature maintenance. Benefits may include lowering afterload (as expressed by reduced SVR), an improved CI, and attenuation of myocardial injury (as assessed by cTnI levels).

Aged↗
PubMedDate not supplied

Minimally invasive reoperative isolated valve surgery: early and mid-term results.

OBJECTIVE: Minimally invasive, nonsternotomy approaches for valve procedures may reduce the risks associated with cardiac surgery after prior sternotomy and may improve outcomes. We analyzed our institutional experience to test this hypothesis. METHODS: Between 1995 and 2002, 498 patients with previous cardiac operations via sternotomy underwent isolated valve surgery: 337 via median sternotomy (aortic = 160; mitral = 177) and 161 via mini-thoracotomy (aortic = 61; mitral = 100). Data were collected prospectively using the New York State Cardiac Surgery Report Form. RESULTS: Preoperative incidences of congestive heart failure, renal disease, and nonelective procedures were higher in the sternotomy group. Hospital mortality was significantly lower with the minimally invasive approach, 5.6% (9/161) versus 11.3% (38/337) (univariate, p = 0.04). However, multivariate analysis (odds ratio: 95% confidence intervals, p value) revealed that chronic obstructive pulmonary disease (6.6: 1.4 to 3.1, p = 0.001), renal disease (4.1: 1.52 to 11.2, p = 0.01), cerebrovascular disease (2.2: 1.03 to 4.78, p = 0.04), and ejection faction <30% (1.5: 0.96 to 5.5, p = 0.06) were associated with increased mortality. While mean bypass time, cross-clamp times, and stroke rates were comparable between groups, patients undergoing minimally invasive valve surgery had no deep wound infections (0% vs 2.4%, p = 0.05), less need for blood products (p = 0.02), and shorter hospital stays (p = 0.009). Five-year survival was higher with minimally invasive techniques as compared to a sternotomy approach (92.4 +/- 2% and 86.0 +/- 2%, respectively, p = 0.08). CONCLUSIONS: Reoperative valve surgery can be safely performed using a nonsternotomy, minimally invasive approach, with at least equal mortality, less hospital morbidity, decreased hospital length of stay, and slightly favorable mid-term survival as compared to sternotomy.

Adolescent↗
PubMedDate not supplied

Higher levels of serum cytokines and myocardial tissue markers during on-pump versus off-pump coronary artery bypass surgery.

Increased Troponin I levels and pro-inflammatory cytokines have been reported in most patients undergoing cardiac surgery, ascribed to the type and extent of surgery, reperfusion injury, and the method of myocardial protection. We investigated their levels in patients undergoing on-pump (CCAB) or off-pump (OPCAB) coronary artery bypass surgery and whether these correlated with the extent of myocardial injury. One hundred twenty patients were prospectively randomized to undergo OPCAB (n = 60) or CCAB (n = 60). Hemodynamic and respiratory data, as well as serum CK-MB mass fraction, Troponin I, and interleukin (IL)-6, IL-8, and IL-10 levels, were collected perioperatively. Demographic, hemodynamic, and respiratory parameters were similar between the two groups. Troponin I was significantly lower in the OPCAB than in the CCAB group, either at the end of ischemia, end of surgery, 6-hour and 24-hour postoperatively (4 +/- 3, 5 +/- 3, 7 +/- 5, and 8 +/- 3 microg/L, vs. 19 +/- 18, 27 +/- 19, 28 +/- 13.5, and 33 +/- 8.5 microg/L, respectively, p < 0.05). Serum cytokine levels in the OPCAB patients were lower compared to the CCAB group at the end of surgery (32 +/- 35, 25 +/- 30, and 40 +/- 30 pg/ml for IL-6, IL-8, and IL-10 vs. 230 +/- 30, 140 +/- 70, and 125 +/- 50 pg/ml, respectively, p < 0.05). Plasma IL-6 levels correlated with the Troponin I levels at the end of surgery in both groups (r = 0.45, p = 0.01). Thus, OPCAB surgery is associated with reduced levels of Troponin I and activation of cytokines, compared to those in the CCAB group. High levels of these factors could correlate with myocardial damage during coronary artery bypass surgery. This finding warrants further laboratory and clinical confirmation in the future.

Adult↗