A substantial number of severely injured patients are under the influence of alcohol, making it i... more A substantial number of severely injured patients are under the influence of alcohol, making it important to understand the effects of acute alcoholic intoxication on the clotting mechanism. Twenty healthy volunteers ingested commercial liquor over a four-hour period and were observed for another three hours. Peak blood alcohol levels were above 200 mg/dL in four subjects and between 100 and 200 mg/dL in 12. Platelet counts, platelet aggregation, and bleeding times were not significantly altered over the seven hours. This study demonstrates that acute alcoholic intoxication in healthy persons does not alter platelet function.
Controversy exists regarding the optimal extent of repair for type A aortic dissection. Our appro... more Controversy exists regarding the optimal extent of repair for type A aortic dissection. Our approach is to replace the ascending aorta, and only replace the aortic root or arch when intimal tears are present in those areas. We examined intermediate outcomes with this approach to acute type A aortic dissection repair. Between March 2005 and October 2016, 195 patients underwent repair of acute type A aortic dissection. Repair was categorized by site of proximal and distal anastomosis and extent of repair. Mean follow-up was 31.0 ± 30.9 months. Kaplan-Meier analysis was used to assess survival. Multiple variable Cox proportional hazards modeling was utilized to identify factors associated with overall mortality. Overall survival was 85.1%, 83.9%, 79.1%, and 74.4% at 6, 12, 36, and 60 months, respectively. Eight patients required reintervention. The cumulative incidence of aortic reintervention at 1 year with death as a competing outcome was 3.95%. Multiple variable regression analysis ...
The Journal of thoracic and cardiovascular surgery, Jan 9, 2017
To evaluate outcomes after mitral valve repair. Between May 1999 and June 2015, 446 patients unde... more To evaluate outcomes after mitral valve repair. Between May 1999 and June 2015, 446 patients underwent mitral valve repair. Isolated mitral valve annuloplasty was excluded. A total of 398 (89%) had degenerative valve disease. Mean follow-up was 5.5 ± 3.8 years. Postoperative echocardiograms were obtained in 334 patients (75%) at a mean of 24.3 ± 13.7 months. Survival was 97%, 96%, 95%, and 94% at 1, 3, 5, and 10 years. Risk factor analysis showed age >60 years and nondegenerative etiology predict death (hazard ratio, 2.91; 95% confidence interval, 1.06-8.02, P = .038; and hazard ratio, 1.87; 95% confidence interval, 1.16-3.02, P = .010, respectively). Considering competing risks due to mortality, the cumulative incidence of reoperation was 2.8%, 4.2%, 5.1%, and 9.6% at 1, 3, 5, and 10 years. Competing risk proportional hazard survival regression identified nondegenerative etiology and previous cardiac surgery as predictors of reoperation, and posterior repair was protective (all ...
The risk of patient-prosthesis mismatch drives most surgeons to select the largest bioprosthesis ... more The risk of patient-prosthesis mismatch drives most surgeons to select the largest bioprosthesis possible during aortic valve replacement, but interactions between the native aortic annulus and valve prosthesis remain poorly defined. We examined the hemodynamic and functional consequences of oversizing contemporary bioprostheses in an in vitro model. Three sizes each (21, 23, and 25 mm) of 5 aortic bioprostheses (Magna, Edwards Lifesciences, Irvine, CA; Trifecta and Epic, St. Jude, St. Paul, MN; and Mosaic and Hancock II, Medtronic, Minneapolis, MN) were tested on a mock annulus in a pulsatile aortic simulator. After the annulus was sized to match each valve, the annulus was decreased by 3 mm and then by 6 mm to simulate oversizing. We measured the effective orifice area and the mean pressure gradient. Changes in prosthetic leaflet behavior and geometric orifice area were assessed with slow-motion video. Statistical analysis used mixed-effects models for repeated-measures data, allo...
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, Jan 6, 2015
Right anterior minithoracotomy with central arterial cannulation is our preferred technique of mi... more Right anterior minithoracotomy with central arterial cannulation is our preferred technique of minimally invasive aortic valve replacement (AVR). We compared perioperative outcomes with this technique to those via sternotomy. Between March 1999 and December 2013, 492 patients underwent isolated AVR via either sternotomy (SAVR, n = 198) or minimally invasive right anterior thoracotomy (MIAVR, n = 294) in our institution. Univariate comparisons between groups were made to evaluate overall outcomes and adverse events. To control treatment selection bias, propensity scores were constructed from core patient characteristics. A propensity score-stratified analysis of outcome and adverse events was then performed. Overall mortality was 2.5 and 1.0% in the SAVR and MIAVR groups, respectively. Hospital and ICU stays were shorter, there was less intraoperative blood product usage, and fewer wound infections in the MIAVR group. There were no differences in other adverse events, including strok...
Background and Aim. While aortic valve replacement for aortic stenosis can be performed safely in... more Background and Aim. While aortic valve replacement for aortic stenosis can be performed safely in elderly patients, there is a need for hemodynamic and quality of life evaluation to determine the value of aortic valve replacement in older patients who may have age-related activity limitation.Materials and Methods. We conducted a prospective evaluation of patients who underwent aortic valve replacement for aortic stenosis with the Hancock II porcine bioprosthesis. All patients underwent transthoracic echocardiography (TTE) and completed the RAND 36-Item Health Survey (SF-36) preoperatively and six months postoperatively.Results. From 2004 to 2007, 33 patients were enrolled with an average age of 75.3 ± 5.3 years (24 men and 9 women). Preoperatively, 27/33 (82%) were New York Heart Association (NYHA) Functional Classification 3, and postoperatively 27/33 (82%) were NYHA Functional Classification 1. Patients had a mean predicted maximumVO2(mL/kg/min) of 19.5 ± 4.3 and an actual maxVO2o...
A substantial number of severely injured patients are under the influence of alcohol, making it i... more A substantial number of severely injured patients are under the influence of alcohol, making it important to understand the effects of acute alcoholic intoxication on the clotting mechanism. Twenty healthy volunteers ingested commercial liquor over a four-hour period and were observed for another three hours. Peak blood alcohol levels were above 200 mg/dL in four subjects and between 100 and 200 mg/dL in 12. Platelet counts, platelet aggregation, and bleeding times were not significantly altered over the seven hours. This study demonstrates that acute alcoholic intoxication in healthy persons does not alter platelet function.
Controversy exists regarding the optimal extent of repair for type A aortic dissection. Our appro... more Controversy exists regarding the optimal extent of repair for type A aortic dissection. Our approach is to replace the ascending aorta, and only replace the aortic root or arch when intimal tears are present in those areas. We examined intermediate outcomes with this approach to acute type A aortic dissection repair. Between March 2005 and October 2016, 195 patients underwent repair of acute type A aortic dissection. Repair was categorized by site of proximal and distal anastomosis and extent of repair. Mean follow-up was 31.0 ± 30.9 months. Kaplan-Meier analysis was used to assess survival. Multiple variable Cox proportional hazards modeling was utilized to identify factors associated with overall mortality. Overall survival was 85.1%, 83.9%, 79.1%, and 74.4% at 6, 12, 36, and 60 months, respectively. Eight patients required reintervention. The cumulative incidence of aortic reintervention at 1 year with death as a competing outcome was 3.95%. Multiple variable regression analysis ...
The Journal of thoracic and cardiovascular surgery, Jan 9, 2017
To evaluate outcomes after mitral valve repair. Between May 1999 and June 2015, 446 patients unde... more To evaluate outcomes after mitral valve repair. Between May 1999 and June 2015, 446 patients underwent mitral valve repair. Isolated mitral valve annuloplasty was excluded. A total of 398 (89%) had degenerative valve disease. Mean follow-up was 5.5 ± 3.8 years. Postoperative echocardiograms were obtained in 334 patients (75%) at a mean of 24.3 ± 13.7 months. Survival was 97%, 96%, 95%, and 94% at 1, 3, 5, and 10 years. Risk factor analysis showed age >60 years and nondegenerative etiology predict death (hazard ratio, 2.91; 95% confidence interval, 1.06-8.02, P = .038; and hazard ratio, 1.87; 95% confidence interval, 1.16-3.02, P = .010, respectively). Considering competing risks due to mortality, the cumulative incidence of reoperation was 2.8%, 4.2%, 5.1%, and 9.6% at 1, 3, 5, and 10 years. Competing risk proportional hazard survival regression identified nondegenerative etiology and previous cardiac surgery as predictors of reoperation, and posterior repair was protective (all ...
The risk of patient-prosthesis mismatch drives most surgeons to select the largest bioprosthesis ... more The risk of patient-prosthesis mismatch drives most surgeons to select the largest bioprosthesis possible during aortic valve replacement, but interactions between the native aortic annulus and valve prosthesis remain poorly defined. We examined the hemodynamic and functional consequences of oversizing contemporary bioprostheses in an in vitro model. Three sizes each (21, 23, and 25 mm) of 5 aortic bioprostheses (Magna, Edwards Lifesciences, Irvine, CA; Trifecta and Epic, St. Jude, St. Paul, MN; and Mosaic and Hancock II, Medtronic, Minneapolis, MN) were tested on a mock annulus in a pulsatile aortic simulator. After the annulus was sized to match each valve, the annulus was decreased by 3 mm and then by 6 mm to simulate oversizing. We measured the effective orifice area and the mean pressure gradient. Changes in prosthetic leaflet behavior and geometric orifice area were assessed with slow-motion video. Statistical analysis used mixed-effects models for repeated-measures data, allo...
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, Jan 6, 2015
Right anterior minithoracotomy with central arterial cannulation is our preferred technique of mi... more Right anterior minithoracotomy with central arterial cannulation is our preferred technique of minimally invasive aortic valve replacement (AVR). We compared perioperative outcomes with this technique to those via sternotomy. Between March 1999 and December 2013, 492 patients underwent isolated AVR via either sternotomy (SAVR, n = 198) or minimally invasive right anterior thoracotomy (MIAVR, n = 294) in our institution. Univariate comparisons between groups were made to evaluate overall outcomes and adverse events. To control treatment selection bias, propensity scores were constructed from core patient characteristics. A propensity score-stratified analysis of outcome and adverse events was then performed. Overall mortality was 2.5 and 1.0% in the SAVR and MIAVR groups, respectively. Hospital and ICU stays were shorter, there was less intraoperative blood product usage, and fewer wound infections in the MIAVR group. There were no differences in other adverse events, including strok...
Background and Aim. While aortic valve replacement for aortic stenosis can be performed safely in... more Background and Aim. While aortic valve replacement for aortic stenosis can be performed safely in elderly patients, there is a need for hemodynamic and quality of life evaluation to determine the value of aortic valve replacement in older patients who may have age-related activity limitation.Materials and Methods. We conducted a prospective evaluation of patients who underwent aortic valve replacement for aortic stenosis with the Hancock II porcine bioprosthesis. All patients underwent transthoracic echocardiography (TTE) and completed the RAND 36-Item Health Survey (SF-36) preoperatively and six months postoperatively.Results. From 2004 to 2007, 33 patients were enrolled with an average age of 75.3 ± 5.3 years (24 men and 9 women). Preoperatively, 27/33 (82%) were New York Heart Association (NYHA) Functional Classification 3, and postoperatively 27/33 (82%) were NYHA Functional Classification 1. Patients had a mean predicted maximumVO2(mL/kg/min) of 19.5 ± 4.3 and an actual maxVO2o...
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Papers by Robbin Cohen