Publications

2010
Mahmood F, Gorman JH, Subramaniam B, Gorman RC, Panzica PJ, Hagberg RC, Lerner AB, Hess PE, Maslow A, Khabbaz KR. Changes in mitral valve annular geometry after repair: saddle-shaped versus flat annuloplasty rings. Ann Thorac Surg. 2010;90 (4) :1212-20.Abstract
BACKGROUND: Saddle-shaped annuloplasty rings are being increasingly used during mitral valve (MV) repair to conform the mitral annulus to a more nonplanar shape and possibly reduce leaflet stress. In this study utilizing three-dimensional transesophageal echocardiography we compared the effects of rigid flat rings with those of the saddle rings on the mitral annular geometry. Specifically we measured the changes in nonplanarity angle (NPA) before and after MV repair. METHODS: Geometric analysis on 38 patients undergoing MV repair for myxomatous and ischemic mitral regurgitation with full flat rings (n = 18) and saddle rings (n = 18) were performed. The acquired three-dimensional volumetric data were analyzed utilizing the "Image Arena" software (TomTec GmBH, Munich, Germany). Specifically, the degree of change in the NPA was calculated and compared before and after repair for both types of rings. RESULTS: Both types of annuloplasty rings resulted in significant changes in the geometric structure of the MV after repair. However, saddle rings lead to a decrease in the NPA (7% for ischemic and 8% for myxomatous MV repairs) (ie, made the annulus more nonplanar), whereas flat rings increased the NPA (7.9% for ischemic and 11.8% for myxomatous MV repairs) (ie, made the annulus less nonplanar); p value 0.001 or less. CONCLUSIONS: Implantation of saddle-shaped rings during MV repair surgery is associated with augmentation of the nonplanar shape of the mitral annulus (ie, decreases NPA). This favorable change in the mitral annular geometry could possibly confer a structural advantage to MV repairs with the saddle rings.
Swaminathan M, Mahmood F. Combined valvular disease: when echocardiography provides the questions and the answers. J Cardiothorac Vasc Anesth. 2010;24 (2) :366.
Robich MP, Matyal R, Chu LM, Feng J, Xu S-H, Laham RJ, Hess PE, Bianchi C, Sellke FW. Effects of neuropeptide Y on collateral development in a swine model of chronic myocardial ischemia. J Mol Cell Cardiol. 2010;49 (6) :1022-30.Abstract
We investigated the role of neuropeptide Y (NPY), abundant in the myocardial sympathetic nervous system and endothelial cells, in angiogenesis during chronic myocardial ischemia. Adult male Yorkshire swine underwent ameroid constrictor placement on the proximal left circumflex coronary artery. After 3 weeks, an osmotic pump was placed to deliver either placebo (control, n=8) or NPY(3-36) (NPY, n=8) to the collateral dependent region. Five weeks after pump placement, after cardiac catheterization and hemodynamic assessment, the heart was harvested for analysis. NPY treated animals demonstrated increased mean arterial pressures and improved left ventricular function (+dP/dt). Cardiac catheterization demonstrated a significant increase in the blush score in the NPY group (p<0.001). Blood flow to the ischemic myocardium was not different between groups at rest or during ventricular pacing. Immunohistochemical double staining for CD-31 and smooth muscle actin demonstrated an increase in capillary and arteriole formation in NPY treated animals (p=0.02 and p<0.001). Immunoblotting showed a significant upregulation of DPPIV (p=0.009) and NPY receptors 1 (p=0.008), 2 (p=0.02) and 5 (p=0.03) in the NPY treated group. Additionally, there was significant upregulation of VEGF (p=0.04), eNOS (p=0.014), phospho-eNOS (ser1177) (p=0.02), and PDGF (p<0.001) in NPY treated group. The anti-angiogenic factors endostatin and angiostatin were significantly decreased in NPY treated animals (endostatin, p=0.03; angiostatin, p=0.04). Exogenous NPY(3-36) resulted in improved myocardial function and increased angiogenesis and arteriogenesis by stimulating growth factor, pro-angiogenic receptor upregulation, and decreasing anti-angiogenic expression, but did not increase blood flow to the ischemic myocardium. NPY may act as a good adjunct to primary agents of therapeutic angiogenesis.
Matyal R, Mahmood F, Hess P, Zhao X, Mitchell J, Maslow A, Gangadharan S, Decamp M. Right ventricular echocardiographic predictors of postoperative supraventricular arrhythmias after thoracic surgery: a pilot study. Ann Thorac Surg. 2010;90 (4) :1080-6.Abstract
BACKGROUND: We used echocardiographically derived myocardial performance index (MPI) to assess changes in global right ventricular function with lung isolation. We hypothesized that changes in MPI with lung isolation may be related to the incidence of postoperative supraventricular tachycardia (SVT). METHODS: Transesophageal echocardiographic examinations were performed after induction of general anesthesia in patients undergoing elective lung resections. Doppler tissue imaging was used to calculate MPI at baseline and 10 minutes after institution of one-lung ventilation (OLV). Arrhythmias occurring within the first 5 postoperative days were recorded. RESULTS: Fifty-nine patients completed the study. Nineteen of 59 patients with a normal baseline MPI (<0.40) had a higher incidence of SVT as compared with patients with an abnormal baseline MPI (42% versus 10%; p = 0.012). The MPI worsened during OLV in 46 patients; a worsening of MPI with lung isolation that was normal at baseline was associated with higher incidence of SVT (57% versus 0%; p = 0.045) compared with a worsening of MPI in patients with an abnormal baseline MPI (13% versus 6%; p = 0.62). A normal baseline MPI value that worsened after OLV, left atrial dilation, and advanced age were identified as predictors of postoperative SVT. CONCLUSIONS: Lung isolation is associated with acute changes in global right ventricular function. A normal baseline MPI that worsens after lung isolation is a better predictor of postoperative SVT as compared with baseline abnormal MPI that does not worsen after lung isolation. Myocardial performance index has a potential to be used as a right ventricular stress test to tolerate OLV before thoracic surgery.
Mahmood F, Swaminathan M. Stuck with a decision: what is the "true" aortic valve area--anatomic, geometric, or effective orifice area?. J Cardiothorac Vasc Anesth. 2010;24 (4) :714-5.
Mahmood F, Swaminathan M. Systolic anterior motion and mitral valve reserve function: which one should we care about?. J Cardiothorac Vasc Anesth. 2010;24 (5) :885-6.
Chen T-H, Matyal R. The management of antiplatelet therapy in patients with coronary stents undergoing noncardiac surgery. Semin Cardiothorac Vasc Anesth. 2010;14 (4) :256-73.Abstract
Whereas the development of coronary stents has been a major breakthrough in the treatment of coronary artery disease, stent thrombosis, associated with myocardial infarction and death, has introduced a new challenge in the care of patients with coronary stents undergoing noncardiac surgery. This review presents the authors' recommendations regarding the optimal management of such patients. Elective surgery should be postponed for at least 6 weeks and optimally 3 months for a bare-metal stent and at least 1 year for a drug-eluting stent. On the other hand, managing a patient undergoing non-elective surgery is more difficult and necessitates a case-by-case assessment of bleeding risk versus thrombotic risk based on patient comorbidities, type of stents present, details of the coronary intervention, and type of surgical procedure. Patients with a risk of bleeding that outweighs the risk of stent thrombosis should discontinue at least clopidogrel, whereas all other patients should continue dual antiplatelet therapy throughout the perioperative period.
Matyal R, Mahmood F, Park KW, Hess P. Preoperative stress testing in high-risk vascular surgery and its association with gender. Gend Med. 2010;7 (6) :584-92.Abstract
BACKGROUND: Despite significant improvement in anesthetic and surgical techniques, the incidence of perioperative myocardial infarction (PMI) and all-cause mortality from any cardiac event during high-risk vascular surgery (abdominal aortic or infrainguinal revascularization procedures) remains high. In addition, there are significant health care costs associated with the management of PMI. OBJECTIVES: The aim of this analysis was to investigate the utility of routine preoperative myocardial stress testing prior to high-risk vascular surgery and the interventions performed based on the results of the testing. The outcome after surgery, based on sex of the patients, was also examined. METHODS: A retrospective analysis was performed on consecutive adult patients who had a positive dipyridamole-thallium stress test prior to high-risk vascular surgery in a university hospital (tertiary care center) between July 2001 and August 2004. The patients' preoperative demographic characteristics, perioperative record, and postoperative course in the hospital were analyzed. Combined major adverse outcome was defined as any incidence of MI, congestive heart failure, arrhythmias, renal failure, or death. RESULTS: Of a total of 503 patients, 160 had a positive stress test prior to high-risk vascular surgery (111 men, 49 women; mean [SD] age, 68 [11] and 70 [12] years, respectively). Men with a positive stress test who had either coronary intervention or perioperative β-blockade prior to surgery had a significant decrease in the incidence of combined major adverse outcomes (P = 0.02). Conversely, women did not have a significant improvement in outcome with either of the preoperative strategies. Using logistic regression, only age and conservative management in men were found to be predictors of adverse outcomes. CONCLUSIONS: In this small retrospective study, men with positive stress tests had fewer adverse events with either preoperative coronary revascularization or perioperative administration of β-adrenergic blocking drugs, compared with men who received no intervention. There were no significant differences in adverse outcomes between women with positive stress tests who received either treatment compared with those who did not receive any treatment.
2009
Matyal R, Panzica P, Tawa NE, Knight PM, Mahmood F. Severe hemodynamic instability during general anesthesia in a professional bodybuilder. J Cardiothorac Vasc Anesth. 2009;23 (2) :208-10.
Maslow A, Schwartz C, Mahmood F, Singh A, Heerdt PM. Case report: paradoxical ventricular septal motion in the setting of primary right ventricular myocardial failure. Can J Anaesth. 2009;56 (7) :510-7.Abstract
PURPOSE: In this report, a case of right ventricular (RV) failure, hemodynamic instability, and systemic organ failure is described to highlight how paradoxical ventricular systolic septal motion (PVSM), or a rightward systolic displacement of the interventricular septum, may contribute to RV ejection. CLINICAL FEATURES: Multiple inotropic medications and vasopressors were administered to treat right heart failure and systemic hypotension in a patient following combined aortic and mitral valve replacement. In the early postoperative period, echocardiographic evaluation revealed adequate left ventricular systolic function, akinesis of the RV myocardial tissues, and PVSM. In the presence of PVSM, RV fractional area of contraction was > or =35% despite akinesis of the primary RV myocardial walls. The PVSM appeared to contribute toward RV ejection. As a result, the need for multiple inotropes was re-evaluated, in considering that end-organ dysfunction was the result of systemic hypotension and prolonged vasopressor administration. After discontinuation of phosphodiesterase inhibitors, native vascular tone returned and the need for vasopressors declined. This was followed by recovery of systemic organ function. Echocardiographic re-evaluation two years later, revealed persistent akinesis of the RV myocardial tissues and PVSM, the latter appearing to contribute toward RV ejection. CONCLUSIONS: This case highlights the importance of left to RV interactions, and how PVSM may mediate these hemodynamic interactions.
Subramaniam B, Panzica PJ, Novack V, Mahmood F, Matyal R, Mitchell JD, Sundar E, Bose R, Pomposelli F, Kersten JR, et al. Continuous perioperative insulin infusion decreases major cardiovascular events in patients undergoing vascular surgery: a prospective, randomized trial. Anesthesiology. 2009;110 (5) :970-7.Abstract
BACKGROUND: A growing body of evidence suggests that hyperglycemia is an independent predictor of increased cardiovascular risk. Aggressive glycemic control in the intensive care decreases mortality. The benefit of glycemic control in noncardiac surgery is unknown. METHODS: In a single-center, prospective, unblinded, active-control study, 236 patients were randomly assigned to continuous insulin infusion (target glucose 100-150 mg/dl) or to a standard intermittent insulin bolus (treat glucose > 150 mg/dl) in patients undergoing peripheral vascular bypass, abdominal aortic aneurysm repair, or below- or above-knee amputation. The treatments began at the start of surgery and continued for 48 h. The primary endpoint was a composite of all-cause death, myocardial infarction, and acute congestive heart failure. The secondary endpoints were blood glucose concentrations, rates of hypoglycemia (< 60 mg/dl) and hyperglycemia (> 150 mg/dl), graft failure or reintervention, wound infection, acute renal insufficiency, and duration of stay. RESULTS: The groups were well balanced for baseline characteristics, except for older age in the intervention group. There was a significant reduction in primary endpoint (3.5%) in the intervention group compared with the control group (12.3%) (relative risk, 0.29; 95% confidence interval, 0.10-0.83; P = 0.013). The secondary endpoints were similar. Hypoglycemia occurred in 8.8% of the intervention group compared with 4.1% of the control group (P = 0.14). Multivariate analysis demonstrated that continuous insulin infusion was a negative independent predictor (odds ratio, 0.28; 95% confidence interval, 0.09-0.87; P = 0.027), whereas previous coronary artery disease was a positive predictor of adverse events. CONCLUSION: Continuous insulin infusion reduces perioperative myocardial infarction after vascular surgery.
Matyal R, Hess PE, Subramaniam B, Mitchell J, Panzica PJ, Pomposelli F, Mahmood F. Perioperative diastolic dysfunction during vascular surgery and its association with postoperative outcome. J Vasc Surg. 2009;50 (1) :70-6.Abstract
OBJECTIVE: To assess the association of perioperative cardiac dysfunction during elective vascular surgery with postoperative outcome. BACKGROUND: Patients with normal systolic function can have isolated diastolic dysfunction. Routine preoperative evaluation of left ventricular (LV) function does not include an assessment of diastolic function for risk stratification. We hypothesized that perioperative assessment of both diastolic and systolic function with transesophageal echo (TEE) may improve our ability to predict postoperative outcome. METHODS: Perioperative TEE examinations were carried out on patients undergoing elective vascular surgery under general anesthesia. Abnormal systolic function was defined as LV ejection fraction (LVEF) <40%. Left ventricular diastolic function was assessed using transmitral flow propagation velocity (Vp); Vp <45 cm/sec was considered abnormal. We determined the association between LV function and the primary outcome of postoperative adverse outcome, defined as one or more adverse events: myocardial infarction (MI), congestive heart failure (CHF), significant arrhythmia, prolonged intubation, renal failure, and death. RESULTS: Three hundred thirteen patients undergoing vascular surgery were studied. We found that 8% (n = 24) of patients had isolated systolic dysfunction, 43% (n = 134) had isolated diastolic dysfunction, and 24% (n = 75) both systolic and diastolic dysfunction. The most common postoperative adverse outcome was CHF 20% (n = 62). By multivariate logistic regression, we found that patient age, Vp, type of surgery, female gender, and renal failure were predictive of postoperative adverse outcome. CONCLUSION: The presence of perioperative diastolic dysfunction as assessed with Vp is an independent predictor of postoperative CHF and prolonged length of stay after major vascular surgery. Patient age, gender, type of surgery, and renal failure were also predictors of outcome. Perioperative systolic function was not a predictor of postoperative outcome in our patients.
Leckie RS, Leckie S, Mahmood F. Perioperative management of a patient with Chagas disease having mitral valve surgery. J Clin Anesth. 2009;21 (4) :282-5.Abstract
A patient with advanced Chagas disease presented with symptoms attributable to dilated cardiomyopathy and mitral regurgitation. Although esophageal involvement is part of the constellation of findings in Chagas, transesophageal echocardiography was safely used to guide the mitral valve surgery.
Matyal R, Karthik S, Subramaniam B, Panzica P, Sundar S, Hagberg R, Jervis K, Mahmood F. Real-time three-dimensional echocardiography for left atrial appendage ligation. Anesth Analg. 2009;108 (5) :1467-9.
Bose R, Matyal R, Panzica P, Karthik S, Subramaniam B, Pawlowski J, Mitchell J, Mahmood F. Transesophageal echocardiography simulator: a new learning tool. J Cardiothorac Vasc Anesth. 2009;23 (4) :544-8.
Mahmood F, Fritsch M, Maslow A. Unanticipated mild-to-moderate aortic stenosis during coronary artery bypass graft surgery: scope of the problem and its echocardiographic evaluation. J Cardiothorac Vasc Anesth. 2009;23 (6) :869-77.
Leissner KB, Mahmood FU. Physiology and pathophysiology at high altitude: considerations for the anesthesiologist. J Anesth. 2009;23 (4) :543-53.Abstract
Millions of people live in, work in, and travel to areas of high altitude (HA). Skiers, trekkers, and mountaineers reach altitudes of 2500 m to more than 8000 m for recreation, and sudden ascents to high altitude without the benefits of acclimatization are increasingly common. HA significantly affects the human body, especially the cardiovascular and pulmonary systems, because of oxygen deprivation due to decreased ambient barometric pressure. Rapid ascents may lead to high-altitude diseases that sometimes have fatal consequences. Other factors, such as severe cold, dehydration, high winds, and intense solar radiation, increase the morbidity of patients at HA. Anesthesiologists working in or visiting areas of higher elevations should become familiar with the human physiology, altered pharmacology, and disease pattern of HA.
Matyal R. Pro: Mitral regurgitation can be reliably assessed under general anesthesia. J Cardiothorac Vasc Anesth. 2009;23 (4) :555-7.
Cummisford K, Manning W, Pawlowski J, Karthik S, Panzica P, Mahmood F. Real-time 3-dimensional transesophageal echocardiographic imaging of a persistent left-sided superior vena cava. J Am Coll Cardiol. 2009;55 (1) :e1.
Mahmood F, Subramaniam B, Gorman JH, Levine RM, Gorman RC, Maslow A, Panzica PJ, Hagberg RM, Karthik S, Khabbaz KR. Three-dimensional echocardiographic assessment of changes in mitral valve geometry after valve repair. Ann Thorac Surg. 2009;88 (6) :1838-44.Abstract
BACKGROUND: Application of annuloplasty rings during mitral valve (MV) repair has been shown to significantly change the mitral annular geometry. Until recently, a comprehensive two-dimensional echocardiographic evaluation of annular geometric changes was difficult owing to its nonplanar orientation. In this study, an analysis of the three-dimensional intraoperative transesophageal echocardiographic evaluation of the MV annulus is presented before and immediately after repair. METHODS: We performed three-dimensional geometric analysis on 75 patients undergoing MV repair during coronary artery bypass graft surgery for mitral regurgitation or myxomatous mitral valve disease. Geometric analysis of the MV was performed before and immediately after valve repair with full rings and annuloplasty bands. The acquired three-dimensional volumetric data were analyzed in the operating room. Specific measurements included annular diameter, leaflet lengths, the nonplanarity angle, and the circularity index. Before and after repair data were compared. RESULTS: Complete echocardiographic assessment of the MV was feasible in 69 of 75 patients (92%) within 2 to 3 minutes of acquisition. Placement of full rings resulted in an increase in the nonplanarity angle or a less saddle shape of the native mitral annulus (137 +/- 14 versus 146 +/- 14; p = 0.002. By contrast, the nonplanarity angle did not change significantly after placement of partial rings. CONCLUSIONS: Mitral annular nonplanarity can be assessed in the operating room. Application of full annuloplasty rings resulted in the mitral annulus becoming more planar. Partial annuloplasty bands did not significantly change the nonplanarity angle. Neither of the two types of rings restored the native annular planarity.

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