Narayana Hrudayalaya Institute of Medical science

Bangalore, India

Narayana Hrudayalaya Institute of Medical science

Bangalore, India

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Adhyapak S.M.,St Johns Medical College Hospital | Adhyapak S.M.,Narayana Hrudayalaya Institute of Medical science 258 A | Menon P.G.,Carnegie Mellon University | Menon P.G.,Guangdong China and QuantMD LLC | Rao Parachuri V.,Narayana Hrudayalaya Institute of Medical science
Interactive Cardiovascular and Thoracic Surgery | Year: 2014

OBJECTIVESSeveral issues that are inherent in the surgical techniques of surgical ventricular restoration (SVR) need specialized devices or techniques to overcome them, which may not always result in optimal outcomes. We used a non-invasive novel in silico modelling technique to study left ventricular (LV) morphology and function before and after SVR. The cardiac magnetic resonance imaging derived actual pre-and postoperative endocardial morphology and function was compared with the in silico analysis of the same.METHODSCardiac magnetic resonance steady state free precession (SSFP) cine images were employed to segment endocardial surface contours over the cardiac cycle. Using the principle of Hausdorff distance to examine phase-to-phase regional endocardial displacement, dyskinetic/akinetic areas were identified at the instant of peak basal contraction velocity. Using a three-dimensional (3D) surface clipping tool, the maximally scarred, dyskinetic or akinetic LV antero-apical areas were virtually resected and a new apex was created. A virtual rectangular patch was created upon the clipped surface LV model by 3D Delaunay triangulation. Presurgical endocardial mechanical function quantified from cine cardiac magnetic resonance, using a technique of spherical harmonics (SPHARM) surface parameterization, was applied onto the virtually clipped and patched LV surface model. Finally, the in silico model of post-SVR LV shape was analysed for quantification of regional left ventricular volumes (RLVVs) and function. This was tested in 2 patients with post-myocardial infarction antero-apical LV aneuryms. Left ventricular mechanical dysynchrony was evaluated by RLVV analysis of pre-SVR, in silico post-SVR and actual post-SVR LV endocardial surface data.RESULTSFollowing exclusion of the scarred areas, the virtual resected LV model demonstrated significantly lesser areas of akinesia. The decreases in regional LV volumes in the in silico modelling were significant and comparable with the actual decreases following SVR. Both the regional end diastolic volume (EDV) and end systolic volume (ESV) at the apex decreased significantly corresponding to greater reductions in apical volumes by the technique of rectangular patch plasty (apical EDV 2.1607 ± 0.20577 to 0.4774 ± 0.1775 ml, P = 0.007; apical ESV 1.9708 ± 0.36451 to 0.442 ± 0.047 ml, P = 0.013).CONCLUSIONSThis pilot study was done using novel in silico techniques for virtual surgical modelling, which helped in accurate estimation and planning of optimal LV restoration by SVR. © 2013 The Author.

Adhyapaka S.M.,St Johns Medical College Hospital | Menon P.G.,SYSU CMU Joint Institute of Engineering | Menon P.G.,SYSU CMU Shunde International Research Institute | Parachuri V.R.,Narayana Hrudayalaya Institute of Medical science | And 2 more authors.
Interactive Cardiovascular and Thoracic Surgery | Year: 2014

OBJECTIVES: In patients with previous myocardial infarction, the remote uninfarcted regions, although contractile, demonstrate dysfunctional wall kinetics because of increased afterload, which improves after surgical ventricular restoration (SVR). We characterized left ventricular (LV) mean myocardial velocity (MMV) through an analysis of endocardial motion and wall thickening (WT) over the cardiac cycle using standard cardiac magnetic resonance (cMR). METHODS: LV endocardial motion and WT from cMR data in 7 heart failure (HF) patients with postinfarction antero apical aneurysm were compared against normal controls to establish a baseline for the mean myocardial velocity during phases of the cardiac cycle. The HF patients' MMV and WT curves were compared with post-SVR data. RESULTS: Global MMV showed significant postoperative improvements in the ejection phase of systole and the early filling phase of diastole. The aneurysmal wall was dyskinetic in both systole and diastole. The remote myocardium preoperatively had a delayed peak velocity during the ejection phase of systole and diminished velocity during early filling in diastole. After SVR, the remote myocardium had an increased MMV with an earlier peaking during the ejection phase and slightly improved early diastolic velocity. WT increased cumulatively during systole and decreased during diastole with improved end-systolic and end-diastolic wall thickness after SVR. The end-systolic wall thickness showed a significant correlation with left ventricular ejection fraction (r2 = 0.89, P = 0.001) and stroke volume (r2 = 0.80, P = 0.02). The MMV had a significant correlation with WT over the phases of the cardiac cycle (r2 = 0.953, P ≤ 0.0001). CONCLUSIONS: In patients with chronic ischaemic heart disease with LV aneurysms/large areas of scar, improvements in the remote myocardial MMV and WT underline LV systolic function improvements after SVR. The persistence of myocardial WT in early diastole is the likely mechanism for incomplete or absence of relief of LV diastolic dysfunction by SVR. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Battu R.,Institute of Medical science | Prasad A.,Narayana Hrudayalaya Institute of Medical science | Kanchi M.,Narayana Hrudayalaya Institute of Medical science
Annals of Cardiac Anaesthesia | Year: 2014

Aims and Objectives: Perioperative optic neuropathy (PON) is a rare, but devastating complication following coronary artery bypass graft surgery (CABG). We performed a retrospective study of PON associated with off-pump CABG (OPCABG) to identify possible risk factors. Materials and Methods: 1442 patients underwent OPCABG over a 10-month period from October 2008 to August 2009; PON was identified in four (0.28%) patients. A retrospective review of the charts was done to identify the patient characteristics, pre-operative status, intra-operative details, and ophthalmic examination details. Friedman test was used to compare the hematocrit (Hct) and the mean arterial pressure (MAP) values across the three time periods: Pre-, intra-and post-operative periods. Results: All four patients were male, diabetic, and in the age range 51-69 years. All patients noted unilateral or bilateral severe visual loss in the immediate post-operative period, which was permanent. All the four patients had statistically significant decrease in the Hct (P < 0.039) and mean arterial blood pressure (P < 0.018) in the intraoperative and post-operative period when compared to pre-operative value. Conclusions: PON is a rare but definite possibility in patients undergoing OPCABG. Diabetes mellitus may be a risk factor. Perioperative hemodynamic abnormalities like decrease in MAP and anemia may play a role in the development of PON in OPCABG.

Banakal S.C.,Narayana Hrudayalaya Institute of Medical science
Annals of Cardiac Anaesthesia | Year: 2010

The use of intraoperative transesophageal echocardiography (TEE) in assessment of the mitral valve repair is well established. It has significantly contributed to the excellent results of mitral valvuloplasty in the current era. This article reviews various two-dimensional echocardiographic planes to assess the mitral valve apparatus, mechanisms of mitral regurgitation, different surgical techniques of repair, complications, and their recognition using TEE.

Changela V.,Narayana Hrudayalaya Institute of Medical science | John C.,Narayana Hrudayalaya Institute of Medical science | Maheshwari S.,Narayana Hrudayalaya Institute of Medical science
Pediatric Cardiology | Year: 2010

We present a large single-center series (>2200 cases) operated for Tetralogy of Fallot (TOF). We analyzed the incidence of associated unusual and uncommonly described cardiac lesions and their diagnostic and therapeutic implications in TOF patients. This retrospective study was conducted by reviewing records of patients operated for TOF at a large tertiary care pediatric cardiac centre. From 2002 to 2008, a total of 2235 cases of TOF were evaluated with echocardiography, cardiac catheterization, and/or cardiac computed tomography followed by cardiac surgery. Known and well-described associations were excluded from the study. Unusual associations were tabulated. Several unusual associations having an incidence >0.1% were detected. These included subaortic membrane (1%), pulmonary venous abnormalities (0.5%), small left ventricle (0.5%), interrupted inferior vena cava (0.5%), mitral valve abnormalities (0.4%), hemitruncus (0.4%), tricuspid valve abnormalities (0.4%), biventricular dysfunction (0.3%), retroaortic innominate vein (0.3%), bicuspid aortic valve (0.2%), and pericardial effusion (0.2%). This series describes unusual, not previously routinely reported cardiac lesions associated with TOF that may affect management and should be sought on preoperative evaluation. We demonstrate that more unusual associations do exist in not infrequent numbers, i.e., a TET is not just a TET. © 2010 Springer Science+Business Media, LLC.

Adhyapak S.M.,St Johns Medical College Hospital | Parachuri V.R.,Narayana Hrudayalaya Institute of Medical science
European Journal of Cardio-thoracic Surgery | Year: 2011

Objective: Surgical ventricular restoration has been the bailout therapy for end-stage heart failure due to ischemic cardiomyopathy in patients not suitable for cardiac transplantation. The recently concluded STICH trial has stated that surgical restoration of the left ventricle does not benefit this subgroup of patients clinically as compared with revascularization alone. The reasons for failure of this trial are multifactorial. The technique of surgical ventricular restoration employed in the STICH trial was circular endoventricular patch plasty. The various drawbacks related to this technique can be offset by a modification based on a mathematical hypothesis, which should result in a more physiological ventricular geometry, with consequent late reverse remodeling and improved left-ventricular performance. Methods: A total of 54 consecutive patients out of 102 patients with post-infarction left-ventricular aneurysms were studied before and 2 years after surgical ventricular restoration by linear endoventricular patch plasty using two-dimensional (2D) echocardiography and contrast ventriculography. Results: Linear endoventricular patch plasty resulted in a decrease in end-diastolic volume (EDV) of 40.2. ml (95% confidence interval (CI): 33.6, 46.7) and stroke volume (SV) of 10.0. ml (95% CI: 6.6, 13.5) and increase in ejection fraction (EF) of 6.7% (95% CI: 5.5, 7.9). There was a further 14% decrease in EDV and SV (30%) at 2 years with increase in EF (20%). There was a persistent significant improvement in sphericity index. The changes in EDV and SV were linearly related (r= 0.72, p< 0.001) and persisted at 2 years following surgery. The change in EDV was linearly related to the EF (r= 0.35, p= 0.02). The left-ventricular shape analysis showed improvements in the anterior and anterolateral segments (effect size = 1.1, p< 0.001) with nonsignificant changes in the inferior segments, conforming to an ellipsoid geometry. Conclusions: Linear endoventricular patch plasty restored a physiological elliptical ventricular geometry with persistent late reverse remodeling. The decreases in EDVs following surgery were significantly linearly proportional to the decreases in SVs at rest, which conforms to the normal left-ventricular geometry. © 2010 European Association for Cardio-Thoracic Surgery.

Prasad A.,Narayana Hrudayalaya Institute of Medical science | Banakal S.,Narayana Hrudayalaya Institute of Medical science | Muralidhar K.,Narayana Hrudayalaya Institute of Medical science
European Journal of Anaesthesiology | Year: 2010

Background and objective Coronary artery bypass graft surgery in high-risk patients may be associated with postoperative renal dysfunction. N-Acetylcysteine is a powerful antioxidant and has been used to prevent contrast-induced renal dysfunction. The efficacy of N-acetylcysteine in preventing postoperative renal dysfunction following off-pump coronary artery bypass graft surgery was studied. Methods A prospective, randomized, controlled study was conducted in patients undergoing off-pump coronary artery bypass graft. The study group (37 patients) received N-acetylcysteine in the perioperative period, whereas the control group (37 patients) did not. The data obtained were analysed using the independent sample t-test (Student's t-test) and x2-test. Results There was no significant difference in the incidence of renal dysfunction between the two groups. Three patients (8.6%) in the N-acetylcysteine group and four (11.4%) in the control group developed renal dysfunction (P value was 1.00). Conclusion N-Acetylcysteine does not have any beneficial effect on renal function in high-risk patients undergoing offpump coronary artery bypass graft. Copyright © European Society of Anaesthesiology.

Nair H.C.,Narayana Hrudayalaya Institute of Medical science
Annals of cardiac anaesthesia | Year: 2010

Trans-esophageal echocardiaography is a sensitive, minimally invasive, diagnostic tool which gives real time functional image of the aorta. It helps in the diagnosis of pathologies of aorta like atherosclerosis, aneurysm and aortic dissection.

Adhyapak S.M.,Narayana Hrudayalaya Institute of Medical science | Parachuri V.R.,Narayana Hrudayalaya Institute of Medical science
Heart failure reviews | Year: 2010

The normal left ventricular shape has been defined as prolate ellipsoid. This shape is an adaptation to evolution. A knowledge of its unique macro and micro architecture forms the cornerstone in the understanding of its complex function. The left ventricle has a unique architecture with three different myofiber orientations, the longitudinal, circumferential and oblique fibers. The oblique orientation of fibers is essential for effective clockwise and anticlockwise torsional movements during systole and diastole, for optimal ventricular ejection and filling. The orientation and fiber angle decide the shape of the ventricle. An ellipsoid shape is vital for optimal function. Pathological disease states such as ischemic heart disease, valvular heart disease and cardiomyopathies cause a loss of obliquity of the myofibers. The myofibers become more horizontal resulting in ventricular dilatation and increased sphericity. The change from ellipsoid to globular shape with disease heralds the onset of left ventricular dysfunction and initiates the cascade of heart failure. Several strategies have been successful in reverting ventricular dilatation and sphericity to a more ellipsoid geometry. Pharmacological therapies like beta blockade and angiotensin converting enzyme inhibition have proven beneficial in early stages of heart failure with pathological remodeling. However, these agents in isolation are limited in reversing pathological remodeling in advanced heart failure. In some cases of advanced heart failure due to postinfarction left ventricular aneurysms, ventricular volume reduction with restoration surgeries have a role in restoring ventricular geometry with beneficial clinical outcomes. Surgical ventricular restoration has progressively evolved from the 1950s. Initially, aneurysmal resection and linear repair was done. This was gradually replaced by endoventricular patch plasty, which had better results. The resulting left ventricle was smaller in size but still continued to have a spherical configuration. Exclusion of the infarct area with a smaller longitudinal patch results in realignment of the non-diseased ventricular fibers with a resulting ellipsoid shape. This ellipsoid shape ensures clinical benefits. The geometry of the endoventricular patch thus holds the key to optimal ventricular shape in these patients. The technique to optimally restore a diseased ventricle to normal continues to evolve. This requires insights into the normal architecture and function, and the pathophysiologic effects of disease.

Adhyapak S.M.,St Johns Medical College Hospital | Parachuri V.R.,Narayana Hrudayalaya Institute of Medical science
Asian Cardiovascular and Thoracic Annals | Year: 2014

Background: In some patients with ischemic cardiomyopathy, despite large increases in ventricular size with decreased cardiac output, the paradox of preserved stroke volume has been observed. Following surgical ventricular restoration, despite marked improvements clinically and in ventricular volumes and ejection fraction, a decrease in stroke volume was observed. Methods: 101 consecutive patients with postinfarction left ventricular aneurysms were studied by 2-dimensional echocardiography and contrast ventriculography at baseline, and 57 of these patients at 1.7 to 2.2 years (mean years) after surgical ventricular restoration. Results: Surgical ventricular restoration resulted in a decrease in end-diastolic volume index of 40.2 mL (95% confidence interval: 33.6-46.7) and stroke volume index of 10.0 mL (95% confidence interval: 6.6-13.5), and an increase in ejection fraction of 6.7% (95% confidence interval: 5.5-7.9). The stroke volume index had a significant linear relationship with the end-diastolic volume index at rest in patients with end-diastolic volume index <150 mL (r=0.64, p<0.001). In patients with end-diastolic volume index >150 mL, this linear relationship was not seen. The change in end-diastolic volume index and stroke volume index had a significant linear relationship (r=0.72, p<0.001) that persisted at 1.95 years after surgery. Conclusions: In ischemic cardiomyopathy, stroke volume increases linearly with increases in end-diastolic volume up to a certain magnitude of end-diastolic volume, beyond which it decreases. Hence, following surgical ventricular restoration, decreases in stroke volume are not a reflection of impaired cardiac function.

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