Feroze Mahmood

Cardiac angiogenic imbalance leads to peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is an often fatal disease that affects pregnant women who are near delivery, and it occurs more frequently in women with pre-eclampsia and/or multiple gestation. The aetiology of PPCM, and why it is associated with pre-eclampsia, remain unknown. Here we show that PPCM is associated with a systemic angiogenic imbalance, accentuated by pre-eclampsia. Mice that lack cardiac PGC-1α, a powerful regulator of angiogenesis, develop profound PPCM. Importantly, the PPCM is entirely rescued by pro-angiogenic therapies. In humans, the placenta in late gestation secretes VEGF inhibitors like soluble FLT1 (sFLT1), and this is accentuated by multiple gestation and pre-eclampsia. This anti-angiogenic environment is accompanied by subclinical cardiac dysfunction, the extent of which correlates with circulating levels of sFLT1. Exogenous sFLT1 alone caused diastolic dysfunction in wild-type mice, and profound systolic dysfunction in mice lacking cardiac PGC-1α. Finally, plasma samples from women with PPCM contained abnormally high levels of sFLT1. These data indicate that PPCM is mainly a vascular disease, caused by excess anti-angiogenic signalling in the peripartum period. The data also explain how late pregnancy poses a threat to cardiac homeostasis, and why pre-eclampsia and multiple gestation are important risk factors for the development of PPCM.

Continuous perioperative insulin infusion decreases major cardiovascular events in patients undergoing vascular surgery: a prospective, randomized trial.

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.

Utility of a transesophageal echocardiographic simulator as a teaching tool.

OBJECTIVE This study was designed to test the hypothesis that simulator-based transesophageal echocardiographic training was a more effective method of training anesthesia residents with no prior experience in echocardiography as compared with conventional methods of training (books, articles, and web-based resources). STUDY DESIGN A prospective randomized study. SETTING An academic medical center (teaching hospital). PARTICIPANTS The participants consisted of first-year anesthesia residents. INTERVENTION The study design was composed of 2 groups: a control group (group 1, conventional group) and a study group (group 2, simulator group). The residents belonging to group 2 (simulator group) received a 90-minute simulator-based teaching session moderated by a faculty experienced in transesophageal echocardiography. Residents belonging to group 1 (conventional group) were asked to review the guidelines of the comprehensive intraoperative transesophageal echocardiographic examination published by the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. They also were encouraged to use other learning resources (eg, textbooks, electronic media, and web-based resources) to understand the underlying concepts of echocardiography. Written pre- and post-test was administered to both groups. MEASUREMENTS AND MAIN RESULTS The groups were compared for the pretest scores by the nonparametric Mann-Whitney U test. Pre- and post-test scores were compared with a Wilcoxon paired test in the individual groups. The results showed a statistically significant difference between the scores of the 2 groups with better scores in the simulation group in the post-training test. CONCLUSION The simulator-based teaching model for transesophageal echocardiography is a better method of teaching the basic concepts of transesophageal echocardiography like anatomic correlation, structure identification, and image acquisition.

Perioperative diastolic dysfunction during vascular surgery and its association with postoperative outcome

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.

Three-Dimensional Echocardiographic Assessment of Changes in Mitral Valve Geometry After Valve Repair

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.

Subclinical Left Ventricular Dysfunction in Preeclamptic Women With Preserved Left Ventricular Ejection Fraction A 2D Speckle-Tracking Imaging Study

Background—Patients with preeclampsia are at risk for cardiovascular disease. Changes in cardiac function are subtle in preeclampsia and are difficult to quantify with conventional imaging. Strain measurements using speckle-tracking echocardiography have been used to sensitively quantify abnormalities in other disease settings. Methods and Results—We evaluated the feasibility and sensitivity of strain imaging using speckle-tracking echocardiography in women with preeclampsia. Forty-seven women were enrolled in this pilot study and 39 were analyzed: 11 with preeclampsia, 17 without a hypertensive disorder, and 11 with nonproteinuric hypertension. Echocardiographic ejection fraction and global peak longitudinal, radial, and circumferential strain were measured. Longitudinal strain was significantly worsened in women with preeclampsia compared with women without a hypertensive disorder (P=0.0001). Similar results were observed for radial strain (P=0.006) and circumferential strain (P=0.03). Women with preeclampsia also had significantly worsened longitudinal (P=0.04), radial (P=0.01), and circumferential (P=0.002) strain compared with women with nonproteinuric hypertension. Women with preeclampsia did not have a significantly different ejection fraction compared with women without a hypertensive disorder (P=0.16) and women with nonproteinuric hypertension (P=0.44). Conclusions—Myocardial strain imaging using speckle tracking is more sensitive than left ventricular ejection fraction to detect differences in left ventricular systolic function in women with and without preeclampsia.

Four cases of cardiopulmonary thromboembolism during liver transplantation without the use of antifibrinolytic drugs

Orthotopic liver transplantation (OLT) is one of the most demanding surgical procedures performed. Intraoperative bleeding can be substantial and related to both surgical and nonsurgical causes. A less common but previously reported phenomenon is intraoperative cardiopulmonary thromboembolism precipitating major patient morbidity and mortality. In this paper, we present four cases of intraoperative thromboembolism during OLT. These cases were performed without the concomitant use of antifibrinolytic drugs. We performed a review and analysis of previously reported cases of intraoperative thromboembolism during OLT. Possible causes of thromboembolism, clinical management, use of thromboelastography, and the role of antifibrinolytic drugs are discussed.

Transesophageal Echocardiography Simulator: A New Learning Tool

RANSESOPHAGEAL ECHOCARDIOGRAPHY (TEE)is a minimally invasive monitoring modality. The initialuse of TEE was limited to the acquisition of images in patientswith suboptimal echo windows during transthoracic echocar-diography. Its role has exponentially expanded to become al-most a standard of care during cardiac surgery and a valuableprocedural adjunct.

Transesophageal Echocardiography and Noncardiac Surgery

The use of transesophageal echocardiography (TEE) for monitoring during cardiac and noncardiac surgery has increased exponentially over the past few decades. TEE has evolved from a diagnostic tool to a monitoring device and a procedural adjunct. The close proximity of the TEE transducer to the heart generates high-quality images of the intracardiac structures and their spatial orientation. The use of TEE in noncardiac and critical care settings is not well studied, and the evidence of the benefits of its use in these settings is lacking. Despite the widespread availability of TEE equipment in US hospitals, less than 30% of anesthesiologists are formally trained in the use of perioperative TEE. In this review, the safety and indications of TEE are reviewed and detailed analysis of the best available evidence in this regard is presented. Landmark trials evaluating the use of TEE and its therapeutic impact in noncardiac surgical setting are critically reviewed. This article details recommendations to familiarize anesthesiologists with TEE technology to exploit it to its fullest potential to achieve better patient monitoring standards and eventually improve outcome. Training of greater numbers of anesthesiologists in TEE is needed to increase awareness of the indications and contraindications. Until relatively inexpensive TEE equipment is available, the initial cost of equipment acquisition remains a significant prohibitive factor limiting its widespread use.

Three-Dimensional Printing of Mitral Valve Using Echocardiographic Data

Three-dimensional (3D) printing has steadily gained traction as a clinical tool. Current applications include developing patient-specific implants, prostheses, and realistic anatomic models for surgical education and planning [(1,2)][1]. In cardiac surgery, patient-specific 3D models of hearts with