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Biomedical subjects

Naresh Trehan

Publications and source records attributed to Naresh Trehan.

At least 19 recordsLinked to original sources
PubMed2006

Cardiac output estimation with a new Doppler device after off-pump coronary artery bypass surgery.

OBJECTIVE: To compare cardiac output (CO), stroke volume (SV), and cardiac index (CI) as estimated with a new, noninvasive Doppler device (Ultrasonic Cardiac Output Monitor [USCOM]; USCOM Ltd, Sydney, Australia) with those measured with the bolus thermodilution (TD) technique. DESIGN: Prospective nonrandomized study. SETTING: Postcardiac surgery recovery unit of a tertiary cardiac center. PARTICIPANTS: Fifty patients after off-pump coronary artery bypass (OPCAB) surgery. MEASUREMENT AND MAIN RESULTS: Both right-sided and left-sided CO were estimated with a USCOM continuous-wave (CW) Doppler device, and CO was determined with the bolus TD technique performed in triplicate. On comparing the right-sided CO, SV, and CI with those of TD, the mean bias was 0.03 L/min, 1.6 mL, and 0.02 L/min/m(2), respectively. The comparison of left-sided CO, SV, and CI with those of TD revealed a means bias of 0.14 L/min, 1.0 mL, and 0.08 L/min/m(2), respectively. CONCLUSION: This study showed excellent agreement between the values for CO, SV, and CI as determined with USCOM and TD. Since there was only 1 time period for CO estimation in each patient with both methods, the stability of this correlation needs to be further investigated over time.

Adult↗
PubMed2006

Coapsys mitral annuloplasty for chronic functional ischemic mitral regurgitation: 1-year results.

BACKGROUND: Untreated functional ischemic mitral regurgitation (MR) leads to reduced survival in patients undergoing coronary artery bypass grafting (CABG). However, mitral repair or replacement increases mortality and morbidity over CABG alone. The Myocor Coapsys annuloplasty system potentially reduces these risks by facilitating MR reduction on a beating heart without atriotomy. We present data from the first 11 patients completing 1-year follow-up of a total of 34 implanted patients. METHODS: Patients referred for CABG with preoperative grade 2 or greater ischemic functional MR were included in this study. Patients with structural valve defects or who demonstrated MR less than grade 2 after CABG, despite hemodynamic challenge, were intraoperatively excluded. Coapsys consists of two epicardial pads connected by a flexible chord implanted by passing the chord across the left ventricle with special instruments without cardiopulmonary bypass. The system was sized to reduce critical valve dimensions and MR. Serial clinical and echocardiographic data were collected out to 1 year. RESULTS: Mean age was 58.1 +/- 6.6 years and mean ejection fraction, 38.5% +/- 7.1%. From baseline to 1-year follow-up, effect on MR grade, MR jet area (cm2), and New York Heart Association class were, respectively, 2.9 +/- 0.5 to 1.1 +/- 0.8, 7.4 +/- 2.9 to 3.0 +/- 1.6, and 2.5 +/- 0.5 to 1.2 +/- 0.4 (all p < 0.05 versus baseline). During follow-up, there were no deaths, device failures, reemergence of grade 3 or 4 MR, heart failure readmission, or valve reoperations. CONCLUSIONS: The Coapsys annuloplasty system is effective in reducing functional ischemic MR and improving NYHA class. The initial data are encouraging and suggest that the device is safe and benefits are sustained at 1 year.

Chronic Disease↗
PubMed2006

Propensity case-matched analysis of off-pump versus on-pump coronary artery bypass grafting in patients with atheromatous aorta.

BACKGROUND: Patients with severe atheromatous disease of the aorta who underwent coronary artery bypass grafting have an increased risk of stroke and death. We hypothesize that in these high-risk patients off-pump coronary artery bypass grafting is associated with lower rates of stroke and mortality. METHODS: From January 1995 through June 2004, a total of 24,107 patients underwent coronary artery bypass grafting. Routine intraoperative transesophageal echocardiography was performed in 18,501, of which 6,991 (29.0%) were found to have severe atheromatous disease in the ascending aorta or aortic arch. Propensity matched-pairs analysis was used to match patients undergoing off-pump coronary artery bypass grafting (n = 3,000) with 3,000 patients undergoing conventional coronary artery bypass grafting by age, sex, ejection fraction, diabetes, preoperative intraaortic balloon pump, congestive heart failure, chronic obstructive pulmonary disease, acute myocardial infarction, peripheral vascular disease, history of stroke or cerebrovascular disease, renal disease, carotid artery disease, atrial fibrillation, emergency surgery, or previous cardiac surgery. RESULTS: Univariate analysis revealed decreased hospital mortality (1.4% versus 3.3%; p < 0.001) and stroke prevalence (0.50% versus 0.97%; p = 0.05) in off-pump coronary artery bypass grafting compared with conventional coronary artery bypass grafting. Multivariate analysis revealed that increased mortality was associated with conventional coronary artery bypass grafting (odds ratio, 2.6; p = 0.001), age (odds ratio, 2.1; p = 0.003), acute myocardial infarction (odds ratio, 1.8; p = 0.03), history of stroke or cerebrovascular disease (odds ratio, 1.6; p = 0.04), congestive heart failure (odds ratio, 2.1; p = 0.04), and diabetes mellitus (odds ratio, 1.9; p = 0.03). Multivariate analysis showed that off-pump coronary artery bypass grafting technique was the only independent predictor of decreased stroke rate (odds ratio, 1.4; p = 0.05). CONCLUSIONS: Off-pump coronary artery bypass grafting surgery in patients with atheromatous disease of the aorta is associated with lower risk of stroke and death. Routine intraoperative evaluation of the aorta is helpful in identifying the disease and directs the appropriate surgical technique.

Adult↗
PubMed2006

Controversies in the use of intraluminal shunts during off-pump coronary artery bypass grafting surgery.

Technical advances have made the performance of multivessel off-pump coronary artery bypass feasible. Snaring and intraluminal shunts are the techniques used for vascular control. Snaring provides a bloodless surgical field, is usually well tolerated by the patient, and is supported by years of clinical experience. Intraluminal shunts aim to achieve hemostasis at the arteriotomy site and to allow antegrade flow to provide myocardial protection. There are unresolved issues regarding whether shunts have a clinical benefit, do provide adequate flow to provide myocardial protection, and whether they cause significant endothelial damage. In this article, we have reviewed the literature to lend perspective to these issues.

Animals↗
PubMed2006

Ascending aortic aneurysm resection: 15 years' experience.

Between September 1989 and June 2004, 148 consecutive patients underwent ascending aortic replacement for aneurysm or dissection. There were 130 males (88%) and 18 females (12%). Their mean age was 46.20 +/- 13.36 years. Fifty-seven patients (39%) were treated for type 1 and type 2 aortic dissection, and 91 (61%) for ascending aortic aneurysm. The Bentall procedure was performed in 81 patients (55%), the Cabrol procedure in 7 (5%), separate ascending aortic replacement and aortic valve replacement or repair was carried out in 24 (16%), and ascending aortic replacement only in 36 (24%). Hospital mortality was 4.05% (6 deaths). On univariate analysis, left ventricular ejection fraction < or = 30%, emergency surgery, contained rupture, concomitant coronary artery bypass grafting, and age > or = 65 years were risk factors for early mortality. However, on multivariate analysis, ejection fraction < or = 30% and contained rupture were the only factors significantly associated with early mortality. The long-term survival rates were 87.2% +/- 3.7% at 5 years, 78.0% +/- 5.6% at 10 years, and 60.9% +/- 9.9% at 15 years. Ascending aortic resection for aneurysm or dissection can be performed with low mortality and morbidity.

Adult↗
PubMed2006

Totally endoscopic coronary artery bypass surgery.

Robotically enhanced surgery is a fast-developing technique that allows totally endoscopic cardiac surgery on both the beating and arrested heart. Between December 2002 and May 2005, 13 patients underwent totally endoscopic coronary bypass using the da Vinci system; 11 operations were on a beating heart and 2 on arrested hearts. The mean time for internal mammary artery mobilization was 42 min. The time for left internal mammary artery-to-left anterior descending artery anastomosis was 20-36 min for totally endoscopic cases. In one patient, the right internal mammary artery was anastomosed to the diagonal artery. No patient required conversion to a median sternotomy. Mean intensive care unit stay was 1.2 days and mean hospital stay was 4.5 days. There was no hospital mortality. All 13 patients had coronary angiography at 3-month intervals, which showed 100% patency in 12 patients while one had 50% anastomotic narrowing for which coronary angioplasty was performed. Using robotic technology, completely endoscopic anastomosis is possible in patients with single-vessel disease. Use of robotics is now extended to achieve complete myocardial revascularization by harvesting both internal mammary arteries in addition to making a small thoracotomy for direct anastomosis.

Adult↗
PubMed2006

Native double-valve endocarditis by Mycobacterium fortuitum following percutaneous coronary intervention.

Infective endocarditis caused by atypical mycobacteria, especially Mycobacterium fortuitum, is rare. Most reported cases involve diseased valves or prosthetic heart valves. Only four cases of native valve endocarditis caused by this organism have been previously reported. Herein is reported a case of native valve endocarditis caused by M. fortuitum; the epidemiology and management of this rare cause of culture-negative endocarditis is discussed.

Angioplasty, Balloon, Coronary↗
PubMed2005

Hemodynamic measurements after cardiac surgery: transesophageal Doppler versus pulmonary artery catheter.

OBJECTIVE: The purpose of this study was to compare hemodynamic data derived from the transesophageal Doppler monitor (Medicina TECO, Berkshire, United Kingdom) against those obtained from a pulmonary artery catheter after coronary artery bypass grafting (CABG). DESIGN: Prospective, nonrandomized, clinical study. SETTING: Single, tertiary referral center. PARTICIPANTS: Thirty-five adult patients. INTERVENTIONS: Cardiac output and hemodynamic variables were measured and compared at 4 predefined time points in patients undergoing elective off-pump CABG surgery from January 2003 through June 2003. MEASUREMENT AND MAIN RESULTS: A total of 140 pairs for cardiac output (CO) data were obtained. Transesophageal cardiac output (TECO) values ranged from 1.9 to 8.7 L/min. Thermodilution cardiac output (TDCO) values ranged from 2.7 to 7.6 L/min. Matched measurements were made with each patient at intervals of 30 minutes. Bland-Altman analysis revealed a mean bias of 1.18 +/- 1.36 L/min, with a correlation (r) of 0.593 (p < 0.000) between TECO and TDCO. Similarly poor correlation was observed among cardiac index (r = 0.523), stroke volume (r = 0.615), systemic vascular resistance (r = 0.595), left ventricular stroke work index (r = 0.594), and right ventricular stroke work index (r = 0.590) measured by an esophageal Doppler monitor against a pulmonary artery catheter. CONCLUSION: A transesophageal Doppler device (Medicina TECO) cannot be relied on as a sole method for monitoring cardiac output and derived hemodynamic variables in patients after CABG surgery.

Aged↗
PubMed2005

Mitral valve repair for ischemic mitral regurgitation in dilated cardiomyopathy.

Ischemic mitral regurgitation contributes to poor survival in patients with heart failure. The intermediate-term outcome of mitral reconstruction in 15 patients who had ischemic dilated cardiomyopathy with mitral regurgitation requiring surgical intervention was studied. They underwent mitral valve repair along with coronary artery bypass surgery. The mitral valve coaptation depth was considered an important parameter in deciding on repair. Ages ranged from 43 to 72 years. Left ventricular ejection fractions were 15-38% (mean, 26.5% +/- 4.3%). The operative technique in all 15 patients was posterior annuloplasty using Dacron felt. At a mean follow-up of 4.6 +/- 1.2 months (1-8 months), postoperative transesophageal echocardiography revealed mild mitral regurgitation in 2 patients and none in 13. There was a significant improvement in New York Heart Association functional class from 3.9 +/- 1.1 to 1.9 +/- 0.3. Mitral valve repair by posterior felt annuloplasty provides favorable results in the intermediate-term in selected patients with ischemic cardiomyopathy and severe left ventricular dysfunction.

Adult↗
PubMed2005

Nosocomial infections and balloon counterpulsation: risk factors and outcome.

Between February and September 2003, 136 (5.3%) of 2,558 patients undergoing cardiac surgery were supported with intra-aortic balloon counterpulsation. There were 71 infected (group 1) and 65 noninfected (group 2) patients. Risk factors for nosocomial infections were identified by univariate and multivariate analysis. On univariate analysis, significant risk factors were operation time, balloon pump duration, ventilation hours, duration of central venous catheter placement, amount of blood transfused, left ventricular ejection fraction<30%, intra- and/or postoperative intra-aortic balloon counterpulsation, surgery under cardiopulmonary bypass, combined procedures, re-exploration, and Acute Physiology And Chronic Health Evaluation (APACHE) II score. On multivariate analysis, ventilation hours and amount of blood transfused were independently associated with group 1. Respiratory tract infections were common in the balloon counterpulsation population (41.1%). Mortality was significantly higher in patients needing balloon pump support (19.9%) compared to controls (1.1%), but it was similar in groups 1 and 2. Recognition of risk factors for postoperative infection in patients undergoing cardiovascular surgical procedures with intra-aortic balloon counterpulsation may help to improve their prognosis and allow more organized surveillance.

Aged↗
PubMed2005

Site-specific detection of bleeder using transesophageal echocardiography.

Transesophageal echocardiography continues to be an indispensable postoperative diagnostic tool for cardiac surgical patients. Transesophageal echocardiography was carried out postoperatively in 30 consecutive hypotensive patients with low cardiac output who had undergone coronary bypass surgery. In 19 of these patients, a cause of low cardiac output requiring surgical intervention was excluded, and they were managed conservatively. In 11 patients, a surgical cause of low cardiac output was indicated: diffuse bleeding from no particular site in 5, and from a specific site in 6. They underwent urgent re-operation, and the echocardiography findings were confirmed on the operating table. Not only is transesophageal echocardiography important in diagnosis, but it is also highly specific in locating the site of bleeding.

Adult↗
PubMed2004

Concomitant carotid endarterectomy and coronary bypass surgery: outcome of on-pump and off-pump techniques.

BACKGROUND: There continues to be a dilemma regarding the best means of surgical management of significant carotid artery disease in patients requiring coronary artery bypass surgery. A combined approach of coronary artery bypass and carotid endarterectomy has shown good results in patients with concomitant carotid and coronary artery disease. We reviewed our results of coronary artery surgery using conventional cardiopulmonary bypass or off-pump techniques and carotid endarterectomy done as a combined procedure. METHODS: Between January 1996 and June 2002, 358 patients underwent concomitant coronary artery bypass and carotid endarterectomy. There were 140 males (84.3%) and 26 females (15.7%) in group I. Group II consisted of 158 males (82.3%) and 34 females (17.7%). One hundred sixty-six patients (group I) were done off pump whereas in 192 patients (group II), the procedure was done using conventional cardiopulmonary bypass. Carotid endarterectomy was performed before coronary artery bypass surgery in both groups. RESULTS: The average number of grafts were 3.4 +/- 0.8 with average operative time of 4.2 +/- 0.4 hours in group I, and 3.3 +/- 0.8 graft with operative time of 5.3 +/- 1.2 hours in group II (p = 0.239 and p < 0.001, respectively). There were 2 deaths (1.2%) in group I and 3 deaths (1.6%) in group II (p = 0.870). No patient from group I and 1 patient (0.5%) from group II had postoperative stroke (p = 0.941). Mean hospital stay was 9.0 +/- 1.2 days in group I and 11.2 +/- 1.7 days in group II (p < 0.001). At mean follow-up of 2.8 +/- 0.9 years in group I, 2 patients (1.2%) had late death due to cardiac failure and contralateral carotid endarterectomy was done in 2 patients (1.2%). Group II had mean follow-up of 2.4 +/- 0.6 years, during which 4 patients (2.1%) had late death and contralateral carotid endarterectomy was done in 3 patients (1.6%). Late stroke was seen in 1 patient (0.6%) from group I and 2 patients (1.0%) from group II. CONCLUSIONS: Concomitant carotid endarterectomy and coronary artery bypass is a safe and effective procedure in patients with significant coronary and carotid artery disease. Equally good results can be reproduced using cardiopulmonary bypass or off-pump techniques for coronary artery surgery, with low morbidity, mortality, and good long-term results.

Aged↗
PubMed2004

Central venous catheter-related blood stream infections: incidence, risk factors, outcome, and associated pathogens.

OBJECTIVE: To determine the incidence, risk factors, outcome, and pathogens of central venous catheter-related bloodstream infections (CVC-BSIs). DESIGN: Prospective study. SETTING: Escorts Heart Institute and Research Centre, New Delhi, India. PARTICIPANTS: One thousand three hundred fourteen consecutive patients undergoing cardiac operations who were admitted to the intensive care unit with CVC. INTERVENTIONS: All patients were assigned into CVC-BSI (n = 35) and non-CVC-BSI (n = 1,279) groups. MEASUREMENT AND MAIN RESULTS: Of the 1,314 patients in the study, 35 (2.6%) had CVC-BSI. On univariate analysis, significant risk factors were use of multilumen catheters, coexistent infections, intra-aortic balloon counterpulsation (IABC), total ventilation hours, emergency surgery, acute physiology, age, chronic health evaluation score (APACHE II), and steroids. On multivariate analysis, duration of catheterization (24.5 +/- 10.9 v 6.1 +/- 3.2; p < 0.001), coexistent infections (57.11% v 2.61%; p < 0.001), IABC (77.1% v 4.1%; p = 0.005), and temperature (38.2 +/- 0.6 v 37.4 +/- 0.3; p < 0.001) were independent predictors of CVC-BSI. Pathogens isolated were Escherichia coli (47%), Acinetobacter species (11.7%), Enterobacter species (5.8%), Proteus species (5.8%), methicillin-resistant Staphylococcus species (11.7%), coagulase-negative Staphylococcus species (5.8%), and Candida (11.7%). The mortality rate in CVC-BSI was 22.9% as compared with 0.2% in non-CVC-BSI cases (p < 0.001). CONCLUSION: By univariate analysis, the risk factors for CVC-BSI were use of multilumen catheters, duration of catheterization, total ventilation hours, IABC, emergency surgery, APACHE II score, coexistent infections, and steroids. On multivariate analysis, duration of catheterization, IABC, coexistent infections, and temperature were independent predictors of CVC-BSI. The mortality was increased with CVC-BSI.

Bacteremia↗
PubMed2004

Spinal (subarachnoid) morphine for off-pump coronary artery bypass surgery.

OBJECTIVE: To study the effects of 8 microg/kg preoperatively administered intrathecal morphine sulfate on extubation time, postoperative pulmonary function, and postoperative analgesia after off-pump coronary artery bypass grafting (OPCAB). DESIGN: A prospective, randomized, double-blind, placebo controlled study. PARTICIPANTS: One hundred adult patients scheduled for elective primary OPCAB. INTERVENTIONS: Patients were randomized to preoperative administration of 8 microg/kg intrathecal morphine sulfate (group 1) with a 25-gauge spinal needle or to receive sterile normal saline placebo subcutaneously (group 2). Anesthetic induction and maintenance were standardized to allow planning for facilitating early tracheal extubation. Multivessel OPCAB was performed with an Octopus stabilizer. Patients were extubated in the intensive care unit by a blinded observer using predefined extubation criteria. MEASUREMENTS AND MAIN RESULTS: Postoperative times to extubation were 9.47 +/- 3.83 hours in group 1 versus 11.25 +/- 3.94 hours in group 2 (P = .025). Postextubation bedside spirometric lung volumes in percentage of preoperative lung volume showed significant differences in group 1 versus group 2 in forced vital capacity, 39.66% +/- 15.42% versus 31.85% +/- 11.65% (P = .016); forced expiratory volume in the first second, 44.8% +/- 16.18% versus 35.97% +/- 13.32% (P = .013); maximum voluntary ventilation, 39.40% +/- 13.57% versus 33.11% +/- 14.80% (P = .056); and expiratory flow rate, 47.76% +/- 24.61% versus 37.37% +/- 4.33% (P = .031). The visual analog pain scores at rest and during coughing at time intervals of 6, 12, 24, and 36 hours postoperatively showed significantly better results in group 1 compared with group 2. The total dose of fentanyl citrate required intraoperatively was significantly less in group 1 (P = .00). One patient in group 1 had a low respiratory rate, which responded to injection naloxone. There was no mortality or neurological complication in either group. CONCLUSION: Intrathecal morphine provided superior quality of analgesia that translated into better maintenance of postoperative lung volume determined by spirometry. This analgesic method also facilitated earlier tracheal extubation without any major respiratory or neurologic complications.

Analgesics, Opioid↗
PubMed2003

A prospective evaluation of hemodynamic instability during off-pump coronary artery bypass surgery.

OBJECTIVE: Despite recognized hemodynamic derangements during cardiac displacement, most patients appear to tolerate the off-pump procedure well. However, some patients unpredictably become hemodynamically unstable requiring emergency cardiopulmonary bypass or intra-aortic balloon pump support. After an experience of 5306 multivessel off-pump coronary artery bypasses (OPCABs), this study was undertaken to determine the factors that would identify the patients who were at a higher risk for the procedure. DESIGN: Prospective clinical investigation. SETTING: Tertiary care academic cardiac care center. PARTICIPANTS: Five hundred consecutive patients undergoing multivessel OPCAB from September to December 2001. INTERVENTIONS: Various cardiac and extracardiac factors were charted in prespecified data-entry forms. Multiple logistic regression analysis was done to determine if any identifiable factors were predictors of a higher risk of unacceptable hemodynamic instability during OPCAB. Institution of IABP support or conversion to CPB were the endpoints of the study. MEASUREMENTS AND MAIN RESULTS: Of the 500 patients studied, significant hemodynamic instability developed in 24 (4.8%) patients. IABP support was instituted in 16 (3.2%) patients, and 8 (1.6%) were converted to CPB. Stepwise logistic regression identified ejection fraction <25% (p < 0.001), myocardial infarction of <1-month duration (p = 0.009), congestive heart failure (p = 0.016), and preoperative hemodynamic instability (p = 0.057) as predictors of conversion during OPCAB. CONCLUSIONS: Patients with low left ventricular ejection fraction <25%, myocardial infarction of <1-month duration, congestive heart failure, or preoperative hemodynamic instability constitute the high-risk group for OPCAB.

Aged↗