Jaishankar Raman | Oregon Health and Science University (original) (raw)

Papers by Jaishankar Raman

Fertility and Sterility, Sep 1, 2006

The Journal of Thoracic and Cardiovascular Surgery, Oct 1, 2012

Intra-aortic balloon pumps are traditionally inserted through the femoral artery, limiting the pa... more Intra-aortic balloon pumps are traditionally inserted through the femoral artery, limiting the patient's mobility. We used alternate approaches of intra-aortic balloon pump insertion to provide temporary and minimally invasive support for patients with decompensating, end-stage heart failure. The present study describes the outcomes with closed-chest, transthoracic intra-aortic balloon pumps by way of the subclavian artery. Methods: During a 3-year period, 20 patients underwent subclavian artery-intra-aortic balloon pump in the setting of end-stage heart failure. The balloon was inserted through a polytetrafluoroethylene graft sutured to the right subclavian artery in 19 patients (95%) and to the left subclavian artery in 1 patient (5%). The goal of support was to bridge to transplantation in 17 patients (85%) and bridge to recovery in 3 patients (15%). The primary outcome measure was death during subclavian artery-intra-aortic balloon pump support. The secondary outcomes included survival to the intended endpoint of bridge to transplantation/bridge to recovery, complications during subclavian artery-intra-aortic balloon pump support (eg, stroke, limb ischemia, brachial plexus injury, dissection, bleeding requiring reoperation, and device-related infection), emergent surgery for worsening heart failure, and ambulation during intra-aortic balloon pump support. Results: The duration of balloon support ranged from 3 to 48 days (mean, 17.3 AE 13.1 days). No patients died during subclavian artery-intra-aortic balloon pump support. Of the 20 patients, 14 (70%) were successfully bridged to transplant or left ventricular-assist device. Two patients (10%) required emergent left ventricularassist device for worsening heart failure. Conclusions: An intra-aortic balloon pump inserted through the subclavian artery is a simple, minimally invasive approach to mechanical support and is associated with limited morbidity and facilitates ambulation in patients with end-stage heart failure.

Journal of Investigative Medicine, Mar 1, 2007

Patients developing acute kidney injury (AKI) after cardiac surgery have increased mortality comp... more Patients developing acute kidney injury (AKI) after cardiac surgery have increased mortality compared with those with stable postoperative renal function. A reliable marker of early AKI in serum or urine has not been found. To test the hypothesis that urinary cystatin C (CyC) increases with greater severity of AKI, we prospectively studied 45 patients undergoing cardiac surgery. Perioperatively, blood and urine were sampled for standard chemistries and CyC (measured by ELISA). AKI was defined as > 25% increase in serum creatinine or the initiation of renal replacement therapy (RRT) within the first 3 postoperative days. AKI developed in 24 patients (53.33%), 5 of whom received RRT (11.1% of the total). The 3-day postoperative maximum increase of urinary CyC from the preoperative baseline was significantly different via ANOVA in those receiving RRT (n = 5) from those with AKI without RRT (n = 16) and those with no AKI (n = 12) (p = .033). This effect is present for the first four postoperative samples, which encompass the first 48 postoperative hours. There was no statistical difference in the preoperative (baseline) urine CyC values. Furthermore, the maximum 3-day increase in perioperative urinary fractional excretion of CyC (FECC) was significantly different across all three groups (no AKI, AKI without RRT, and RRT), p = .01. Similar to urinary CyC, this difference was seen for the first 48 postoperative hours. There was no statistical significance to the preoperative values across all three groups. Increased urinary cystatin C excretion in the early postoperative period precedes the development of severe AKI (requiring RRT) and correlates with AKI severity. Urinary CyC and FECC are promising biomarkers of AKI following adult cardiac surgery. Table 1 Clinical Characteristics of University of Chicago Cardiac Surgery Study Subjects (N= 45)

PubMed, 1990

We studied retrospectively, 412 consecutive Asian patients undergoing coronary artery bypass graf... more We studied retrospectively, 412 consecutive Asian patients undergoing coronary artery bypass grafting between January 1st, 1982 and June 30th, 1987. The mean age was 55 +/- 9 years at operation with a 70.5% male predominance. Patients of Chinese origin accounted for 60.9%, Indonesian for 26.4%, Indian 9.9% and Malaysian 2.6%. Chronic stable angina was the most consistent presenting symptom in 71% and 49% had at least one myocardial infarction in the past. Fifty percent were hypertensive and 26% diabetic. Left main stem coronary artery obstruction was evident in 21.6% and the coronary arteries diffusely diseased in 53%. An average of 3.8 +/- 0.4 grafts were performed per patient using reversed saphenous vein, and endarterectomies were necessitated in 27.1%. The small calibre of coronary arteries in Asian patients was reflected by 54% of grafted vessels having a luminal diameter of 1.5 mm. The early mortality rate and the peri-operative myocardial infarction rate was 1.2% in each instance. A mean follow-up of 30 months revealed a late mortality of 1.9% and 76% of patients were in NYHA Functional Class I. This study suggests that despite a high incidence of hypertension, diabetes and diffuse coronary artery disease Asian patients tolerate coronary artery bypass graft surgery well and obtain significant benefit from it.

PubMed, Nov 1, 1988

A consecutive series of 73 patients aged 75 years and above underwent coronary artery bypass graf... more A consecutive series of 73 patients aged 75 years and above underwent coronary artery bypass graft surgery during a 6 year period. Pre-operatively unstable angina (61.6%) and congestive heart failure (10.9%) were significant presenting features. Triple vessel disease accounted for 61.6% of cases while 26% had left main coronary obstruction. The mean number of grafts per patient was 3.2 +/- 0.9. Combined procedures such as valve replacement were done in 16.2% of patients. The hospital mortality rate was 2.7% and there was not a single recordable case of peri-operative myocardial infarction. Significant complications post-operatively were atrial arrhythmias (43.8%), segmental pulmonary atelectasis (43.8%) and renal problems (15%). Of the sixty patients followed up at an average of 27.7 months, 58 were in NYHA Functional Class I. Good patient selection and careful monitoring leads to encouraging results with coronary artery bypass grafting in the elderly.

Heart Lung and Circulation, Mar 1, 2011

Background: Functional mitral regurgitation (FMR) is primarily due to abnormalities of the ventri... more Background: Functional mitral regurgitation (FMR) is primarily due to abnormalities of the ventricular muscle in the presence of normal mitral leaflets. Present surgical treatment options address the mitral valve annulus and leaflets but not the ventricular muscle. We discuss the evolution of a concept that describes a ventricular solution to this problem, and report preliminary clinical results from the first five subjects implanted with the latest version of this device. Methods: Evaluation of safety and efficacy of the latest version of the BACE TM (Basal Annuloplasty of the Cardia Externally) Device was done first in sheep with rapid ventricular pacing to induce severe MR. The BACE Device was implanted around the base of the heart and chambers on the device filled with normal saline through the subcutaneous ports under echocardiogram until there was no evidence of MR. Once MR was effectively reduced, the chest was closed and the animals recovered, with clinical and echocardiographic analysis through six months of follow-up. Human studies were done with in a similar manner, with subjects that were already undergoing concomitant open-chest coronary artery bypass graft (CABG) surgery. Five subjects with ischaemic MR and triple vessel coronary artery disease were first implanted with the BACE Device, applied epicardially on a beating heart without use of cardiopulmonary bypass, before coronary artery bypass grafting was done. Results: In five sheep, epicardial application of the BACE Device effectively reduced mitral regurgitation from Grade 4 to Grade 0, and the effect was sustained through six months despite ongoing pacing. Terminal studies at six months showed no adhesion to the silicone band. All five human subjects were male, NYHA Class III, with LVEF of 20-40%. Epicardial application and adjustment of the BACE Device was performed safely on a beating heart with effective reduction in FMR to grade <1. All five subjects had three bypass grafts. Reduction in MR was sustained for at least six months and there were no unanticipated or device-related adverse events. Conclusion: Epicardial application and adjustment of the BACE Device can be performed safely without CPB with effective reduction in MR.

Springer eBooks, Oct 12, 2008

part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of ... more part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

Journal of Patient Safety, Jan 12, 2016

This study aimed to demonstrate the use of a systems theorybased accident analysis technique in h... more This study aimed to demonstrate the use of a systems theorybased accident analysis technique in health care applications as a more powerful alternative to the chain-of-event accident models currently underpinning root cause analysis methods. Method: A new accident analysis technique, CAST [Causal Analysis based on Systems Theory], is described and illustrated on a set of adverse cardiovascular surgery events at a large medical center. The lessons that can be learned from the analysis are compared with those that can be derived from the typical root cause analysis techniques used today. Results: The analysis of the 30 cardiovascular surgery adverse events using CAST revealed the reasons behind unsafe individual behavior, which were related to the design of the system involved and not negligence or incompetence on the part of individuals. With the use of the system-theoretic analysis results, recommendations can be generated to change the context in which decisions are made and thus improve decision making and reduce the risk of an accident. Conclusions: The use of a systems-theoretic accident analysis technique can assist in identifying causal factors at all levels of the system without simply assigning blame to either the frontline clinicians or technicians involved. Identification of these causal factors in accidents will help health care systems learn from mistakes and design system-level changes to prevent them in the future.

Heart Lung and Circulation, 2023

Heart Lung and Circulation, 2021

European Heart Journal, Oct 1, 2022

Heart Lung and Circulation, Dec 1, 2000

Background-Atrial flutter (AFL) and atrial fibrillation (AF) frequently coexist, yet the specific... more Background-Atrial flutter (AFL) and atrial fibrillation (AF) frequently coexist, yet the specific relationship between these arrhythmias, and particularly whether sustained AFL leads to AF, is unknown. Methods and Results-We investigated the electrophysiological consequences of chronic AFL using an ovine anatomic right atrial Y-lesion model. AFL was induced in 7 animals, and 4 remained in sinus rhythm (controls). Sheep were monitored for spontaneous conversion of AFL to AF. Six of 7 sheep sustained AFL for 28 days. In 1 of 7 sheep, spontaneous conversion of AFL to AF occurred on day 5. AFL produced a highly significant fall in right and left atrial refractoriness (AERP, PϽ0.001), with 74Ϯ10% of the reduction occurring by day 3. Right atrial conduction velocity also fell significantly (baseline 89Ϯ9 cm/s versus day 28 64Ϯ14 cm/s, PϽ0.001) but over a slower time course. AERP and conduction velocity changes coincided with a characteristic biphasic decrease and increase in the AFL cycle length. The excitable gap (percent of AFL cycle length) increased from 13Ϯ3% at baseline to 46Ϯ8% by day 28 (PϽ0.001). Sustained AF (Ͼ30 seconds) was not inducible at baseline but after 28 days of AFL could be induced in 6 of 6 sheep by critically timed single or multiple extrastimuli delivered either in sinus rhythm or AFL. There was no significant change in any parameter in control sheep. Conclusions-In this model, AFL produced electrical remodeling and the substrate for sustained AF. However, spontaneous conversion to AF was uncommon, and the development of AF was dependent on specific triggers.

Global surgery, 2015

Access to the heart and closure of the resultant incisions and wounds have been considered major ... more Access to the heart and closure of the resultant incisions and wounds have been considered major impediments to the growth of cardiac surgery. Nevertheless, during the 1980s and 1990s, the sternotomy was the most commonly performed surgical access procedure in the world. We discuss the evolution of various techniques to allow access to the heart and surrounding structures. Methods of closure of these incisions are also highlighted as these techniques evolve.

Heart Lung and Circulation, Jun 1, 2023

Journal of Investigative Medicine, Mar 1, 2006

Heart, Lung and Circulation

Regular and Young Investigator Award Abstracts

Journal of the American Chemical Society