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Featured researches published by Bala Ramanan.


Annals of Surgery | 2013

Long-term results of a randomized controlled trial of a nonoperative strategy (watchful waiting) for men with minimally symptomatic inguinal hernias.

Robert J. Fitzgibbons; Bala Ramanan; Shipra Arya; Scott A. Turner; Xue Li; James O. Gibbs; Domenic J. Reda

Objective:To assess the long-term crossover (CO) rate in men undergoing watchful waiting (WW) as a primary treatment strategy for their asymptomatic or minimally symptomatic inguinal hernias. Background:With an average follow-up of 3.2 years, a randomized controlled trial comparing WW with routine repair for male patients with minimally symptomatic inguinal hernias led investigators to conclude that WW was an acceptable option [JAMA. 2006;295(3):285–292]. We now analyze patients in the WW group after an additional 7 years of follow-up. Methods:At the conclusion of the original study, 254 men who had been assigned to WW consented to longer-term follow-up. These patients were contacted yearly by mail questionnaire. Nonresponders were contacted by phone or e-mail for additional data collection. Results:Eighty-one of the 254 men (31.9%) crossed over to surgical repair before the end of the original study, December 31, 2004, with a median follow-up of 3.2 (range: 2–4.5) years. The patients have now been followed for an additional 7 years with a maximum follow-up of 11.5 years. The estimated cumulative CO rates using Kaplan-Meier analysis was 68%. Men older than 65 years crossed over at a considerably higher rate than younger men (79% vs 62%). The most common reason for CO was pain (54.1%). A total of 3 patients have required an emergency operation, but there has been no mortality. Conclusions:Men who present to their physicians because of an inguinal hernia even when minimally symptomatic should be counseled that although WW is a reasonable and safe strategy, symptoms will likely progress and an operation will be needed eventually.


Journal of The American College of Surgeons | 2012

Development and Validation of a Bariatric Surgery Mortality Risk Calculator

Bala Ramanan; Prateek K. Gupta; Himani Gupta; Xiang Fang; R. Armour Forse

BACKGROUNDnWhile the epidemic of obesity continues to plague America, bariatric surgery is underused due to concerns for surgical risk among patients and referring physicians. A risk score estimating postoperative mortality (OS-MRS) exists, however, is limited by consideration of only 12 preoperative variables, failure to separate open and laparoscopic cases, a lack of robust statistical analyses, risk factors not being weighted, and being applicable to only gastric bypass surgery. The objective of this study was to develop a validated risk calculator for 30-day postoperative mortality after bariatric surgery.nnnSTUDY DESIGNnThe National Surgical Quality Improvement Program (NSQIP) dataset (2006 to 2008) was used. Patients undergoing bariatric surgery for morbid obesity (n = 32,889) were divided into training (n = 21,891) and validation (n = 10,998) datasets. Multiple logistic regression analysis was performed on the training dataset. The model fit from the training dataset was maintained and was used to estimate mortality probabilities for all patients in the validation dataset.nnnRESULTSnThirty-day mortality was 0.14%. Seven independent predictors of mortality were identified: peripheral vascular disease, dyspnea, previous percutaneous coronary intervention, age, body mass index, chronic corticosteroid use, and type of bariatric surgery. This risk model was subsequently validated. The model performance was very similar between the training and the validation datasets (c-statistics, 0.80 and 0.82, respectively). The high c-statistics indicate excellent predictive performance. The risk model was used to develop an interactive risk calculator.nnnCONCLUSIONSnThis risk calculator has excellent predictive ability for mortality after bariatric procedures. It is anticipated that it will aid in surgical decision-making, informed patient consent, and in helping patients and referring physicians to assess the true bariatric surgical risk.


Journal of Vascular Surgery | 2014

Unplanned readmissions after vascular surgery

Prateek K. Gupta; Sara Fernandes-Taylor; Bala Ramanan; Travis L. Engelbert; K. Craig Kent

OBJECTIVEnExisting literature on readmission after vascular surgery is limited. The upcoming reduction in Medicare reimbursement for institutions with high readmission rates mandates an accurate understanding of this issue. In this study, we characterize the frequency and causes of 30-day unplanned readmissions after elective vascular surgery.nnnMETHODSnPatients who underwent elective carotid endarterectomy (CEA), endovascular aortic repair (EVAR), open abdominal aortic aneurysm (oAAA) repair, or infrainguinal bypass grafting (BPG) were identified from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) 2011 database (n = 11,246). Multivariable logistic regression was used to determine variables that contributed to 30-day unplanned readmissions for each surgery type.nnnRESULTSnThe unadjusted unplanned readmission rates after the four vascular procedures ranged from 6.5% for CEA to 15.7% for BPG. In multivariable analyses, patient comorbidities were associated with unplanned readmission after BPG and CEA (P < .05), whereas postoperative complications were more consistently associated with unplanned readmission after EVAR and oAAA repair (P < .05). For all procedures, complications leading to readmission developed more frequently after discharge. Thirty-day mortality was significantly higher in readmitted patients after BPG (1.9% vs 0.3%), EVAR (3.9% vs 0.1%), and CEA (2.2% vs 0.2%; P < .001 for each), but not after oAAA repair.nnnCONCLUSIONSnSelect comorbidities and postoperative complications contribute to unplanned readmissions after vascular surgery. The characteristics of readmitted patients vary with the type of procedure. Interventions designed to mitigate these factors have the potential to reduce unplanned readmissions but likely need to vary with the type of vascular treatment.


Chest | 2013

Impact of COPD on Postoperative Outcomes: Results From a National Database

Himani Gupta; Bala Ramanan; Prateek K. Gupta; Xiang Fang; Ann Polich; Ariel Modrykamien; Dan Schuller; Lee E. Morrow

BACKGROUNDnAlthough COPD affects large sections of the population, its effects on postoperative outcomes have not been rigorously studied. The objectives of this study were to describe the prevalence of COPD in patients undergoing surgery and to analyze the associations between COPD and postoperative morbidity, mortality, and hospital length of stay.nnnMETHODSnPatients with COPD who underwent surgery were identified from the National Surgical Quality Improvement Program database (2007-2008). Univariate and multivariate analyses were performed on this multicenter, prospective data set (N = 468,795).nnnRESULTSnCOPD was present in 22,576 patients (4.82%). These patients were more likely to be older, men, white, smokers, and taking corticosteroids and had a lower BMI (P < .0001 for each). Median length of stay was 4 days for patients with COPD vs 1 day in those without COPD (P < .0001). Thirty-day morbidity rates were 25.8% and 10.2% for patients with and without COPD, respectively (P < .0001). Thirty-day death rates were 6.7% and 1.4% for patients with and without COPD, respectively (P < .0001). After controlling for > 50 comorbidities through logistic regression modeling, COPD was independently associated with higher postoperative morbidity (OR, 1.35; 95% CI, 1.30-1.40; P < .0001) and mortality (OR, 1.29; 95% CI, 1.19-1.39; P < .0001). Multivariate analyses with each individual postoperative complication as the outcome of interest showed that COPD was associated with increased risk for postoperative pneumonia, respiratory failure, myocardial infarction, cardiac arrest, sepsis, return to the operating room, and renal insufficiency or failure (P < .05 for each).nnnCONCLUSIONSnCOPD is common among patients undergoing surgery and is associated with increased morbidity, mortality, and length of stay.


Journal of Vascular Surgery | 2012

Development and validation of a risk calculator for prediction of mortality after infrainguinal bypass surgery.

Prateek K. Gupta; Bala Ramanan; Thomas G. Lynch; Abhishek Sundaram; Jason N. MacTaggart; Himani Gupta; Xiang Fang; Iraklis I. Pipinos

OBJECTIVEnFor peripheral arterial disease, infrainguinal bypass grafting (BPG) carries a higher perioperative risk compared with peripheral endovascular procedures. The choice between the open and endovascular therapies is to an extent dependent on the expected periprocedural risk associated with each. Tools for estimating the periprocedural risk in patients undergoing BPG have not been reported in the literature. The objective of this study was to develop and validate a calculator to estimate the risk of perioperative mortality ≤30 days of elective BPG.nnnMETHODSnWe identified 9556 patients (63.9% men) who underwent elective BPG from the 2007 to 2009 National Surgical Quality Improvement Program data sets. Multivariable logistic regression analysis was performed to identify risk factors associated with 30-day perioperative mortality. Bootstrapping was used for internal validation. The risk factors were subsequently used to develop a risk calculator.nnnRESULTSnPatients had a median age of 68 years. The 30-day mortality rate was 1.8% (n = 170). Multivariable logistic regression analysis identified seven preoperative predictors of 30-day mortality: increasing age, systemic inflammatory response syndrome, chronic corticosteroid use, chronic obstructive pulmonary disease, dependent functional status, dialysis dependence, and lower extremity rest pain. Bootstrapping was used for internal validation. The model demonstrated excellent discrimination (C statistic, 0.81; bias-corrected C statistic, 0.81) and calibration. The validated risk model was used to develop an interactive risk calculator using the logistic regression equation.nnnCONCLUSIONSnThe validated risk calculator has excellent predictive ability for 30-day mortality in a patient after an elective BPG. It is anticipated to aid in surgical decision making, informed patient consent, preoperative optimization, and consequently, risk reduction.


Journal of Vascular Surgery | 2013

Risk index for predicting perioperative stroke, myocardial infarction, or death risk in asymptomatic patients undergoing carotid endarterectomy

Prateek K. Gupta; Bala Ramanan; Jason N. MacTaggart; Abhishek Sundaram; Xiang Fang; Himani Gupta; Jason M. Johanning; Iraklis I. Pipinos

OBJECTIVEnThe latest guidelines recommend performance of carotid endarterectomy (CEA) on asymptomatic patients with high-grade carotid stenosis, only if the combined perioperative stroke, myocardial infarction (MI), or death risk is ≤3%. Our objective was to develop and validate a risk index to estimate the combined risk of perioperative stroke, MI, or death in asymptomatic patients undergoing elective CEA.nnnMETHODSnAsymptomatic patients who underwent an elective CEA (nxa0= 17,692) were identified from the 2005-2010 National Surgical Quality Improvement Program, a multicenter, prospective database. Multivariable logistic regression analysis was performed with primary outcome of interest being the composite of any stroke, MI, or death during the 30-day periprocedural period. Bootstrapping was used for internal validation. A risk index was created by assigning weighted points to each predictor using the β-coefficients from the regression analysis.nnnRESULTSnFifty-eight percent of the patients were men with a median age of 72 years. Thirty-day incidences of stroke, MI, and death were 0.9% (nxa0= 167), 0.6% (nxa0= 108), and 0.4% (nxa0= 72), respectively. The combined 30-day stroke, MI, or death incidence was 1.8% (nxa0= 324). On multivariable analysis, six independent predictors were identified and a risk index created by assigning weighted points to each predictor using the β-coefficients from the regression analysis. The predictors included age in years (<60: 0 point; 60-69: -1 point; 70-79: -1 point; ≥80: 2 points), dyspnea (2 points), chronic obstructive pulmonary disease (3 points), previous peripheral revascularization or amputation (3 points), recent angina within 1 month (4 points), and dependent functional status (5 points). Patients were classified as low (<3%),xa0intermediate (3%-6%), or high (>6%) risk for combined 30-day stroke, MI, or death, based on a total point score ofxa0<4, 4-7, and >7, respectively. There were 15,249 patients (86.2%) in the low-risk category, 2233 (12.6%) in the intermediate-risk category, and 210 (1.2%) in the high-risk category.nnnCONCLUSIONSnThe validated risk index can help identify asymptomatic patients who are at greatest risk for 30-day stroke, MI, and death after CEA, thereby aiding patient selection.


European Journal of Vascular and Endovascular Surgery | 2012

Endovascular Repair of Abdominal Aortic Aneurysm does not Improve Early Survival versus Open Repair in Patients Younger than 60 Years

Prateek K. Gupta; Bala Ramanan; Thomas G. Lynch; H. Gupta; Xiang Fang; Marcus Balters; Jason M. Johanning; G.M. Longo; Jason N. MacTaggart; Iraklis I. Pipinos

OBJECTIVESnMultiple randomised trials have demonstrated lower perioperative mortality after endovascular aneurysm repair (EVAR) compared to open surgical repair for infrarenal abdominal aortic aneurysms (AAAs). However, in these trials the mortality advantage for EVAR is being lost within 2 years of repair and the patients evaluated are relatively older with no study specifically comparing EVAR and open repair for patients younger than 60 years of age.nnnDESIGNnA retrospective analysis of prospectively collected data.nnnMATERIALS AND METHODSnPatients younger than 60 years of age who underwent EVAR and open surgical repair for elective infrarenal AAA were identified from the 2007-09 National Surgical Quality Improvement Program (NSQIP) - a prospective database maintained at 237 centres across the United States. Univariate and multivariate analyses were performed.nnnRESULTSnOf the 651 patients, 369 (56.7%) underwent EVAR and 282 (43.3%) underwent open repair. Thirty-day mortality for EVAR and open repair were 1.1% and 0.4%, respectively. This was not significantly different on univariate (Pxa0=xa00.22) as well as multivariate (Pxa0=xa00.69) analysis after controlling for other co-morbidities. On multivariate analysis, body mass index, history of stroke and bleeding disorder prior to surgery were associated with a higher 30-day mortality after AAA repair (combined open and EVAR).nnnCONCLUSIONSnThese contemporary results demonstrate that the 30-day mortality rate after open repair is similar to that after EVAR in patients younger than 60 years with infrarenal AAA.


Journal of Vascular Surgery | 2013

Development of a risk index for prediction of mortality after open aortic aneurysm repair

Bala Ramanan; Prateek K. Gupta; Abhishek Sundaram; Himani Gupta; Jason M. Johanning; Thomas G. Lynch; Jason N. MacTaggart; Iraklis I. Pipinos

OBJECTIVEnOpen infrarenal abdominal aortic aneurysm (oAAA) repair is associated with significant morbidity and mortality. Although there has been a shift toward endovascular repair, many patients continue to undergo an open repair due to anatomic considerations. Tools currently existing for estimation of periprocedural risk in patients undergoing open aortic surgery have certain limitations. The objective of this study was to develop a risk index to estimate the risk of 30-day perioperative mortality after elective oAAA repair.nnnMETHODSnPatients who underwent elective oAAA repair (n = 2845) were identified from the American College of Surgeons 2007 to 2009 National Surgical Quality Improvement Program (NSQIP), a prospective database maintained at >250 centers. Univariable and multivariable analyses were performed to evaluate risk factors associated with 30-day mortality after oAAA repair and a risk index was developed.nnnRESULTSnThe 30-day mortality after oAAA repair was 3.3%. Multivariable analysis identified six preoperative predictors of mortality, and a risk index was created by assigning weighted points to each predictor using the β-coefficients from the regression analysis. The predictors included dyspnea (at rest: 8 points; on moderate exertion: 2 points; none: 0 points), history of peripheral arterial disease requiring revascularization or amputation (3 points), age >65 years (3 points), preoperative creatinine >1.5 mg/dL (2 points), female gender (2 points), and platelets <150,000/mm(3) or >350,000/mm(3) (2 points). Patients were classified as low (<7%), intermediate (7%-15%), and high (>15%) risk for 30-day mortality based on a total point score of <8, 8 to 11, and >11, respectively. There were 2508 patients (88.2%) patients in the low-risk category, 278 (9.8%) in the intermediate-risk category, and 59 (2.1%) in the high-risk category.nnnCONCLUSIONSnThis risk index has excellent predictive ability for mortality after oAAA repair and awaits validation in subsequent studies. It is anticipated to aid patients and surgeons in informed patient consent, preoperative risk assessment, and optimization.


Journal of Vascular Surgery | 2012

In-hospital and postdischarge venous thromboembolism after vascular surgery

Bala Ramanan; Prateek K. Gupta; Abhishek Sundaram; Thomas G. Lynch; Jason N. MacTaggart; B. Timothy Baxter; Jason M. Johanning; Iraklis I. Pipinos

OBJECTIVEnRecent single-center reports demonstrate a high (up to 10%) incidence of postoperative venous thromboembolism (VTE) after major vascular surgery. Moreover, vascular patients rarely receive prolonged prophylaxis despite evidence that it reduces thromboembolic events after discharge. This study used a national, prospective, multicenter database to define the incidence of overall and postdischarge VTE after major vascular operations and assess risk factors associated with VTE development.nnnMETHODSnPatients with VTE who underwent elective vascular procedures (nxa0= 45,548) were identified from the 2007-2009 National Surgical Quality Improvement Program (NSQIP) database. The vascular procedures included carotid endarterectomy (CEA; nxa0= 20,785), open thoracoabdominal aortic aneurysm (TAAA) repair (nxa0= 361), thoracic endovascular aortic repair (TEVAR; nxa0= 732), open abdominal aortic (OAA) surgery (nxa0= 6195), endovascular aneurysm repair (EVAR; nxa0= 7361), and infrainguinal bypass graft (BPG; nxa0= 10,114). Univariable and multivariable analyses were performed to ascertain risk factors associated with VTE.nnnRESULTSnVTE was diagnosed in 187 patients (1.3 %) who underwent aortic surgery, with TAAA repair having the highest rate of VTE (4.2%), followed by TEVAR (2.2%), OAA surgery (1.7%), and EVAR (0.7%). In this subgroup, pulmonary embolisms (PE) were diagnosed in 52 (0.4%) and deep venous thrombosis (DVT) in 144 (1%). VTE rates were 1.0% and 0.2% for patients who underwent a BPG or CEA, respectively. Forty-one percent of all VTEs were diagnosed after discharge. The median (interquartile range) number of days from surgery to PE and DVT were 10 (5-15) and 10 (4-18), respectively. On multivariable analyses, type of surgical procedure, totally dependent functional status, disseminated cancer, postoperative organ space infection, postoperative cerebrovascular accident, failure to wean from ventilator ≤48 hours, and return to the operating room were significantly associated with development of VTE. In those experiencing a DVT or PE, overall mortality increased from 1.5% to 6.2% and from 1.5% to 5.7% respectively (Pxa0< .05 for both).nnnCONCLUSIONSnPostoperative VTE is associated with the type of vascular procedure and is highest after operations in the chest and abdomen/pelvis. About 40% of VTE events in elective vascular surgery patients were diagnosed after discharge, and the presence of VTE was associated with a quadrupled mortality rate. Future studies should evaluate the benefit of DVT screening and postdischarge VTE prophylaxis in high-risk patients.


Journal of Vascular Surgery | 2014

Postdischarge outcomes after endovascular abdominal aortic aneurysm repair

Prateek K. Gupta; Travis L. Engelbert; Bala Ramanan; Xiang Fang; Dai Yamanouchi; John R. Hoch; Charles W. Acher

OBJECTIVEnPerioperative outcomes after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA) have been rigorously studied; however, inpatient and postdischarge outcomes have not been separately analyzed. The objective of this study was to examine postdischarge 30-day outcomes after elective EVAR.nnnMETHODSnPatients who underwent an elective EVAR for AAA (n = 11,229) were identified from the American College of Surgeons 2005-2010 National Surgical Quality Improvement Project database. Univariable and multivariable logistic regression analyses were performed.nnnRESULTSnThe median length of hospital stay was 2 days (interquartile range, 1-3 days). Overall 30-day mortality was 1.0% (n = 117), with 31% (n = 36) of the patients dying after discharge. Overall 30-day morbidity was 10.7% (n = 1204), with 40% (n = 500) of the morbidities being postdischarge. The median time of death and complication was 9 and 3 days, respectively, after surgery. Eighty-eight percent of the wound infections (n = 205 of 234), 33% of pneumonia (n = 44 of 133), and 55% of venous thromboembolism (n = 36 of 65) were postdischarge. Multivariable analyses showed age, congestive heart failure, admission from nursing facility, postoperative pneumonia, myocardial infarction, and renal failure were independently associated with postdischarge mortality, and peripheral arterial disease, female gender, previous cardiac surgery, age, smoking, and diabetes with postdischarge morbidity (P < .05 for all).nnnCONCLUSIONSnPatient characteristics associated with a higher risk for postdischarge adverse events after EVAR were identified. Whether improved predischarge surveillance and close postdischarge follow-up of identified high-risk patients will further improve 30-day outcomes after EVAR needs to be prospectively studied.

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Prateek K. Gupta

University of Tennessee Health Science Center

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Iraklis I. Pipinos

University of Nebraska Medical Center

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Jason N. MacTaggart

University of Nebraska Medical Center

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Jason M. Johanning

University of Nebraska Medical Center

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Thomas G. Lynch

University of Nebraska Medical Center

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Travis L. Engelbert

University of Wisconsin Hospital and Clinics

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Charles W. Acher

University of Wisconsin Hospital and Clinics

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