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Dive into the research topics where Mercedes K.C. Dullum is active.

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Featured researches published by Mercedes K.C. Dullum.


Stroke | 2001

Stroke After Coronary Artery Bypass: Incidence, Predictors, and Clinical Outcome

Sotiris C. Stamou; Peter C. Hill; George Dangas; Albert J. Pfister; Steven W. Boyce; Mercedes K.C. Dullum; Ammar S. Bafi; Paul J. Corso

Background and Purpose— Early postoperative stroke is a serious adverse event after coronary artery bypass grafting (CABG). This study sought to investigate risk factors, prevalence, and prognostic implications of postoperative stroke in patients undergoing CABG. Methods— We investigated the predictors of postoperative stroke (n=333, 2%) in 16 528 consecutive patients who underwent CABG between September 1989 and June 1999 in our institution. Predictors of postoperative stroke were identified by logistic regression analysis. Results— Among the preoperative and postoperative factors, significant correlates of stroke included (1) chronic renal insufficiency (P <0.001), (2) recent myocardial infarction (P =0.01), (3) previous cerebrovascular accident (P <0.001), (4) carotid artery disease (P <0.001), (5) hypertension (P <0.001), (6) diabetes (P =0.001), (7) age >75 years (P =0.008), (8) moderate/severe left ventricular dysfunction (P =0.01), (9) low cardiac output syndrome (P <0.001), and (10) atrial fibrillation (P <0.001). Postoperative stroke was associated with longer postoperative stay (11±4 versus 7±3 days for patients without stroke, P <0.001) and with higher in-hospital mortality (14% versus 2.7% for patients without stroke;P <0.001). Conclusions— Stroke after CABG is associated with high short-term morbidity and mortality. Increased stroke risk can be predicted by preoperative and postoperative clinical factors.


Circulation | 2006

Effect of Clopidogrel Premedication in Off-Pump Cardiac Surgery Are We Forfeiting the Benefits of Reduced Hemorrhagic Sequelae?

Emmanouil I. Kapetanakis; Diego A. Medlam; Kathleen R. Petro; Elizabeth Haile; Peter C. Hill; Mercedes K.C. Dullum; Ammar S. Bafi; Steven W. Boyce; Paul J. Corso

Background— Premedication with clopidogrel has reduced thrombotic complications after percutaneous coronary revascularization procedures. However, because of the enhanced and irreversible platelet inhibition by clopidogrel, patients requiring surgical revascularization have a higher risk of bleeding complications and transfusion requirements. A principal benefit of surgical coronary revascularization without cardiopulmonary bypass is its lower hemorrhagic sequelae. The purpose of this study was to evaluate the effect of preoperative clopidogrel administration in the incidence of hemostatic reexploration, blood product transfusion rates, morbidity, and mortality in patients undergoing off-pump coronary artery bypass graft surgery using a large patient sample and a risk-adjusted approach. Methods and Results— Two hundred eighty-one patients (17.9%) did and 1291 (82.1%) did not receive clopidogrel before their surgery, for a total of 1572 patients undergoing isolated off-pump coronary artery bypass graft surgery between January 2000 and June 2002. Risk-adjusted logistic regression analyses and a matched pair analyses by propensity scores were used to assess the association between clopidogrel administration and reoperation as a result of bleeding, intraoperative and postoperative blood transfusions received, and the need for multiple transfusions. Hemorrhage-related preoperative risk factors identified in the literature and those found significant in a univariate model were used. The clopidogrel group had a higher likelihood of hemostatic reoperations (odds ratio [OR], 5.1; 95% confidence interval [CI], 2.47 to 10.47; P<0.01) and an increased need in overall packed red blood cell (OR, 2.6; 95% CI, 1.94 to 3.60; P<0.01), multiple unit (OR, 1.6; 95% CI, 1.07 to 2.48; P=0.02), and platelet (OR, 2.5; 95% CI, 1.77 to 3.66; P<0.01) transfusions. Surgical outcomes and operative mortality (1.4% versus 1.4%; P=1.00) were not statistically different. Conclusions— Clopidogrel administration in the cardiology suite increases the risk for hemostatic reoperation and the requirements for blood product transfusions during and after off-pump coronary artery bypass graft surgery.


The Annals of Thoracic Surgery | 2002

Elimination of cardiopulmonary bypass improves early survival for multivessel coronary artery bypass patients.

Mitchell J. Magee; Kathleen A. Jablonski; Sotiris C. Stamou; Albert J. Pfister; Todd M. Dewey; Mercedes K.C. Dullum; James R. Edgerton; Syma L. Prince; Tea E. Acuff; Paul J. Corso; Michael J. Mack

BACKGROUND Coronary artery bypass graft (CABG) surgery performed without cardiopulmonary bypass (CPB) is currently increasing in clinical practice. Decreased morbidity associated with off-pump (OP) CABG in selected risk groups examined in relatively small, single institution groups has been the focus of most recent studies. The purpose of this study was to determine the independent impact of CPB on early survival in all isolated multivessel CABG patients undergoing surgery in two large institutions with established experience in OPCABG techniques. METHODS A review of two large databases employed by multiple surgeons in the hospitals of two institutions identified 8,758 multivessel CABG procedures performed from January 1998 through July 2000. In all, 8,449 procedures were included in a multivariate logistic regression analysis to determine the relative impact of CPB on mortality independent of known risk factors for mortality. Procedures were also divided into two treatment groups based on the use of CPB: 6,466 had CABG with CPB (CABG-CPB), 1,983 had CABG without CPB (OPCABG). Disparities between groups were identified by univariate analysis of 17 preoperative risk factors and treatment groups were compared by Parsonnets risk stratification model. Finally, computer-matched groups based on propensity score for institution selection for OPCABG were combined and analyzed by a logistic regression model predicting risk for mortality. RESULTS CABG-CPB was associated with increased mortality compared with OPCABG by univariate analysis, 3.5% versus 1.8%, despite a lower predicted risk in the CABG-CPB group. CPB was associated with increased mortality by multiple logistic regression analysis with an odds ratio of 1.79 (95% confidence interval = 1.24 to 2.67). An increased risk of mortality associated with CPB was also determined by logistic regression analysis of the combined computer-matched groups based on OPCABG-selection propensity scores with an odds ratio of 1.9 (95% confidence interval = 1.2 to 3.1). CONCLUSIONS Elimination of CPB improves early survival in multivessel CABG patients. Rigorous attempts to statistically account for selection bias maintained a clear association between CPB and increased mortality. Larger multiinstitutional studies are needed to confirm these findings and determine the most appropriate application of OPCABG.


The Annals of Thoracic Surgery | 2002

Stroke after conventional versus minimally invasive coronary artery bypass

Sotiris C. Stamou; Kathleen A. Jablonski; Albert J. Pfister; Peter C. Hill; Mercedes K.C. Dullum; Ammar S. Bafi; Steven W. Boyce; Kathleen R. Petro; Paul J. Corso

BACKGROUND Postoperative stroke is a serious complication after coronary artery bypass grafting with cardiopulmonary bypass (on-pump), and portends higher morbidity and mortality. It is unknown whether an off-pump cardiopulmonary bypass (OPCAB) approach may yield a lower stroke rate over conventional on-pump coronary artery bypass grafting. METHODS From June 1994 to December 2000, OPCAB was performed in 2,320 patients and compared with 8,069 patients who had on-pump coronary artery bypass grafting, during the same period of time. The patients undergoing OPCAB were randomly matched to on-pump patients by propensity score. A logistic regression model was used to test the difference in the postoperative stroke rate between OPCAB and on-pump procedures controlling for the correlation between matched sets. A multiple logistic regression model predicting the risk of stroke adjusted by stroke risk factors and operation type was also computed. RESULTS Matches by propensity score were found for 72% of the patients undergoing OPCAB. Patients undergoing on-pump coronary artery bypass grafting were 1.8 (95% confidence interval 1.0 to 3.1, p = 0.03) times more likely to suffer a stroke postoperatively than OPCAB patients after controlling for preoperative risk factors through matching. Independent predictors of stroke identified from the multiple logistic model included on-pump operation (versus OPCAB operation), female gender, 4 to 6 vessels grafted (versus <4 grafts), hypertension, history of previous cerebrovascular accident, carotid artery disease, chronic obstructive pulmonary disease, and depressed ejection fraction. CONCLUSIONS Off-pump cardiopulmonary bypass avoids the risks of cardiopulmonary bypass and atrial trauma. A substantially lower stroke rate suggests that OPCAB is a neurologically safe treatment option for revascularization.


American Journal of Cardiology | 2000

Atrial Fibrillation After Beating Heart Surgery

Sotiris C. Stamou; George Dangas; Peter C. Hill; Albert J. Pfister; Mercedes K.C. Dullum; Steven W. Boyce; Ammar S. Bafi; Jorge M. Garcia; Paul J. Corso

Postoperative atrial fibrillation (AF) is a frequent adverse event after coronary artery bypass grafting (CABG) and may negatively affect the early clinical outcome. We sought to investigate the risk factors, prevalence, and prognostic implications of postoperative AF in patients submitted to CABG without cardiopulmonary bypass (off-pump). The study population comprised 969 patients, 645 men (67%) and 324 women (33%) who had off-pump CABG at the Washington Hospital Center from January 1987 to May 1999. Preoperative AF patients were excluded (n = 15). Two hundred six patients (age 69 +/- 10 years, 137 men [66%]) developed AF, whereas 763 patients (age 61 +/- 12 years, 508 men [67%]) did not. Predictors of AF included age >75 years (odds ratio [OR] 3.0, 95% confidence interval [CI] 1.9 to 4.5; p <0.001), history of stroke (OR 2.1, CI 1.2 to 3.7; p = 0. 007), postoperative pleural effusion requiring thoracentesis (OR 3.2, CI 1.0 to 9.4; p = 0.03), and postoperative pulmonary edema (OR 5.1, CI 1.2 to 21; p = 0.02). Minimally invasive direct CABG was associated with a lower incidence of AF (OR 0.4, CI 0.3 to 0.7; p <0. 001). AF was associated with a prolonged postoperative hospital stay (9 +/- 6 days AF vs 6 +/- 5 days no AF, p <0.001). In-hospital mortality was significantly higher in AF patients (3% AF vs 1% no AF, p = 0.009). Patients with persistent AF had a higher postoperative in-hospital stroke rate than patients without persistent AF (9% vs 0. 6%, p <0.001). AF after beating heart surgery is associated with a higher in-hospital morbidity, mortality, and prolonged hospital stay. A minimally invasive surgical approach (minimally invasive direct CABG) is associated with a lower risk of AF.


The Annals of Thoracic Surgery | 2000

Beating heart surgery in octogenarians: perioperative outcome and comparison with younger age groups ☆

Sotiris C. Stamou; George Dangas; Mercedes K.C. Dullum; Albert J. Pfister; Steven W. Boyce; Ammar S. Bafi; Jorge M. Garcia; Paul J. Corso

BACKGROUND Octogenarians have higher morbidity and mortality rates (9% to 16%) after coronary artery bypass grafting with cardiopulmonary bypass, compared with younger patients. METHODS We compared the perioperative outcome and hospital stay after coronary artery bypass grafting without cardiopulmonary bypass (off-pump) from January 1987 to May 1999, among patients older than 80 years (n = 71), patients between 70 and 79 years (n = 228), and patients whose age ranged from 60 to 69 years (n = 296). In comparison with younger patients, more octogenarians were female (51% versus 39% in patients aged 70 to 79 years and 35% in those aged 60 to 69 years, p = 0.04), they had previous myocardial infarction more frequently (48% versus 47% versus 34%, respectively, p = 0.008), and were operated on urgently (69% versus 56% versus 52%, respectively, p = 0.04). RESULTS Postoperative complications that were significantly higher in octogenarians compared with younger groups included pneumonia (6% in octogenarians versus 2% in patients aged 70 to 79 years and 0% in patients aged 60 to 69 years, p = 0.001) and atrial fibrillation (47% versus 32% versus 21%, respectively, p<0.001). By multivariate logistic regression analysis, age over 80 years was an independent predictor of prolonged hospital stay (odds ratio = 2.7, 95% confidence interval, 1.4 to 5, p<0.001). The in-hospital mortality rate was higher in octogenarians (6% versus 3% for 70 to 79 year-olds and 0.3% for 60 to 69 year-olds, p = 0.006). CONCLUSIONS When appropriately applied in patients older than 80 years, off-pump coronary artery bypass grafting can be done with acceptable postoperative morbidity, mortality, and hospital stay.


The Annals of Thoracic Surgery | 2000

Beating heart versus conventional single-vessel reoperative coronary artery bypass

Sotiris C. Stamou; Albert J. Pfister; George Dangas; Mercedes K.C. Dullum; Steven W. Boyce; Ammar S. Bafi; Jorge M. Garcia; Paul J. Corso

BACKGROUND Reoperative (redo) coronary artery bypass grafting (CABG) with cardiopulmonary bypass (on-pump) is associated with a higher morbidity and mortality than first-time CABG. It is unknown, however, whether CABG without cardiopulmonary bypass (off-pump) may yield an improved clinical outcome over conventional on-pump redo CABG. METHODS We compared the perioperative outcomes of patients with single-vessel disease who underwent on-pump (n = 41) versus off-pump (n = 91) redo CABG between April 1992 and July 1999. The two groups were similar with respect to baseline characteristics and risk stratification: mean Parsonnet scores were 26 +/- 9 for on-pump versus 24 +/- 8 for off-pump patients (p = nonsignificant). RESULTS On-pump redo patients had a higher rate of postoperative transfusions (58% on-pump versus 27% off-pump, p = 0.001), prolonged ventilatory support (17% on-pump versus 4% off-pump, p = 0.03), and a higher rate of postoperative atrial fibrillation (29% on-pump versus 14% off-pump, p = 0.04). On-pump redo CABG was also associated with prolonged postoperative length of stay (8 +/- 4 days on-pump versus 5 +/- 2 days off-pump, p < 0.001). In-hospital mortality was significantly higher in on-pump than in off-pump patients (10% versus 1%, p = 0.03). CONCLUSIONS Single-vessel off-pump redo CABG can be performed safely with a lower operative morbidity and mortality than on-pump CABG and an abbreviated hospital stay compared with conventional on-pump redo CABG.


The Journal of Thoracic and Cardiovascular Surgery | 2003

Clinical and six-month angiographic evaluation of coronary arterial graft interrupted anastomoses by use of a self-closing clip device: a multicenter prospective clinical trial

Randall K. Wolf; Edwin L. Alderman; Michael P. Caskey; Allen R Raczkowski; Mercedes K.C. Dullum; Dwight C Lundell; Arthur C Hill; Nan Wang; Michael A. Daniel

OBJECTIVES To evaluate the safety and effectiveness of a self-closing surgical clip with an interrupted technique in left internal thoracic artery to left anterior descending artery bypass grafting. METHODS Eighty-two patients were enrolled and treated (February 2000 through August 2001) in a prospective, nonrandomized, multicenter trial. Left internal thoracic artery to left anterior descending artery anastomoses were performed in 60 off-pump coronary artery bypasses (73%), 12 conventional coronary artery bypass grafting (15%), and 10 minimally invasive direct coronary artery bypass (12%) procedures. Angiograms (64 to 383 days, mean 200 days) were obtained on 63 patients (77%). Qualitative and quantitative angiographic assessment was performed by an independent core laboratory. RESULTS The self-closing surgical clip was used for 82 left internal thoracic artery to left anterior descending artery interrupted anastomoses without the requirement for knot tying or primary suture management. Minimum left internal thoracic artery to left anterior descending artery anastomosis time was 3 minutes. There was one perioperative and one late death (both not heart related) and one reexploration for bleeding unrelated to the anastomotic site. FitzGibbon grades were as follows: A (n = 60, 95.2%), B (n = 3, 4.8%) including one kinked left internal thoracic artery, and O (n = 0, 0%). Quantitative analysis (n = 57) showed mean lumen diameters of left internal thoracic artery proximal to the anastomosis of 2.1 mm, at anastomosis of 2.0 mm, and in the left anterior descending artery distal to the anastomosis of 1.9 mm. The average ratio of the anastomosis to the left anterior descending artery diameter was 1.14 (0.45 to 1.93). Anastomotic stenosis as a percentage of average left internal thoracic artery to left anterior descending artery diameter was -2.3%, comparing favorably with results (23% to 24%) reported from the Patency, Outcomes, Economics, Minimally invasive direct coronary artery (POEM) bypass study. CONCLUSIONS The interrupted technique, facilitated by a self-closing anastomotic clip, yields favorable 6-month angiographic results when compared with other published studies.


Stroke | 2001

Stroke After Coronary Artery Bypass

Sotiris C. Stamou; Peter C. Hill; George Dangas; Albert J. Pfister; Steven W. Boyce; Mercedes K.C. Dullum; Ammar S. Bafi; Paul J. Corso

Background and Purpose— Early postoperative stroke is a serious adverse event after coronary artery bypass grafting (CABG). This study sought to investigate risk factors, prevalence, and prognostic implications of postoperative stroke in patients undergoing CABG. Methods— We investigated the predictors of postoperative stroke (n=333, 2%) in 16 528 consecutive patients who underwent CABG between September 1989 and June 1999 in our institution. Predictors of postoperative stroke were identified by logistic regression analysis. Results— Among the preoperative and postoperative factors, significant correlates of stroke included (1) chronic renal insufficiency (P <0.001), (2) recent myocardial infarction (P =0.01), (3) previous cerebrovascular accident (P <0.001), (4) carotid artery disease (P <0.001), (5) hypertension (P <0.001), (6) diabetes (P =0.001), (7) age >75 years (P =0.008), (8) moderate/severe left ventricular dysfunction (P =0.01), (9) low cardiac output syndrome (P <0.001), and (10) atrial fibrillation (P <0.001). Postoperative stroke was associated with longer postoperative stay (11±4 versus 7±3 days for patients without stroke, P <0.001) and with higher in-hospital mortality (14% versus 2.7% for patients without stroke;P <0.001). Conclusions— Stroke after CABG is associated with high short-term morbidity and mortality. Increased stroke risk can be predicted by preoperative and postoperative clinical factors.


Stroke | 2001

Stroke After Coronary Artery Bypass : Incidence, Predictors, and Clinical Outcome Editorial Comment: Incidence, Predictors, and Clinical Outcome

Sotiris C. Stamou; Peter C. Hill; George Dangas; Albert J. Pfister; Steven W. Boyce; Mercedes K.C. Dullum; Ammar S. Bafi; Paul J. Corso; Brian Silver

Background and Purpose— Early postoperative stroke is a serious adverse event after coronary artery bypass grafting (CABG). This study sought to investigate risk factors, prevalence, and prognostic implications of postoperative stroke in patients undergoing CABG. Methods— We investigated the predictors of postoperative stroke (n=333, 2%) in 16 528 consecutive patients who underwent CABG between September 1989 and June 1999 in our institution. Predictors of postoperative stroke were identified by logistic regression analysis. Results— Among the preoperative and postoperative factors, significant correlates of stroke included (1) chronic renal insufficiency (P <0.001), (2) recent myocardial infarction (P =0.01), (3) previous cerebrovascular accident (P <0.001), (4) carotid artery disease (P <0.001), (5) hypertension (P <0.001), (6) diabetes (P =0.001), (7) age >75 years (P =0.008), (8) moderate/severe left ventricular dysfunction (P =0.01), (9) low cardiac output syndrome (P <0.001), and (10) atrial fibrillation (P <0.001). Postoperative stroke was associated with longer postoperative stay (11±4 versus 7±3 days for patients without stroke, P <0.001) and with higher in-hospital mortality (14% versus 2.7% for patients without stroke;P <0.001). Conclusions— Stroke after CABG is associated with high short-term morbidity and mortality. Increased stroke risk can be predicted by preoperative and postoperative clinical factors.

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Paul J. Corso

MedStar Washington Hospital Center

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Steven W. Boyce

MedStar Washington Hospital Center

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Sotiris C. Stamou

Missouri Baptist Medical Center

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Ammar S. Bafi

MedStar Washington Hospital Center

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Peter C. Hill

MedStar Washington Hospital Center

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Kathleen R. Petro

MedStar Washington Hospital Center

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Jorge M. Garcia

MedStar Washington Hospital Center

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Emmanouil I. Kapetanakis

MedStar Washington Hospital Center

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Elizabeth Haile

MedStar Washington Hospital Center

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