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Biomedical subjects

Fred A Crawford

Publications and source records attributed to Fred A Crawford.

At least 19 recordsLinked to original sources
PubMed2006

Complete repair of conotruncal defects with an interatrial communication: oxygenation, hemodynamic status, and early outcome.

BACKGROUND: Complete repair of conotruncal defects frequently uses maintenance of an interatrial communication. Postoperative right ventricular dysfunction may be characterized by elevated right atrial pressure and decreased systemic oxygen saturation owing to right-to-left shunting at the atrial level. METHODS: From January 1996 to December 2005, 112 patients younger than 6 months of age underwent complete repair of tetralogy of Fallot or truncus arteriosus. An interatrial communication was used in 80 of 112 patients (71%). Hemodynamic data were determined during the first 48 hours after surgery. RESULTS: In patients with an atrial communication, mean oxygen saturation reached a nadir of 94% +/- 6%, and mean arterial PO2 a nadir of 73 +/- 25 mm Hg at 16 to 24 hours after surgery; both increased during the second 24 hours. At hospital discharge, median oxygen saturation was 98% (range, 86% to 100%). During the first 48 hours, mean oxygen saturation was less than 90% in 13 patients; the only multivariate risk factor was younger patient age. Mean right atrial pressure was greater than 10 mm Hg in 30 patients; multivariate risk factors were older patient age and repair with a transannular patch. CONCLUSIONS: After complete repair of conotruncal defects using an interatrial communication, systemic oxygenation reaches a nadir at 24 hours after surgery, and improves by the time of hospital discharge. Clinically significant desaturation occurs in a small minority of patients. Infants undergoing repair before 2 months of age are at higher risk for systemic desaturation. The effects of an interatrial communication on systemic oxygenation should not be considered a contraindication to complete repair in early infancy.

Cardiac Surgical Procedures↗
PubMed2006

Preoperative statin treatment is associated with reduced postoperative mortality and morbidity in patients undergoing cardiac surgery: an 8-year retrospective cohort study.

BACKGROUND: Cardiac surgical procedures can be associated with significant morbidity and mortality. Recently, it has been recognized that statins might induce multiple biologic effects independent of lipid lowering that could potentially ameliorate adverse surgical outcomes. Accordingly, this study tested the central hypothesis that pretreatment with statins before cardiac surgery would reduce adverse postoperative surgical outcomes. METHODS: Demographic and outcomes data were collected retrospectively for 3829 patients admitted for planned cardiac surgery between February 1994 and December 2002. Statin pretreatment occurred in 1044 patients who were comparable with non-statin-pretreated (n = 2785) patients with regard to sex, race, and age. Primary outcomes examined included postoperative mortality (30-day) and a composite morbidity variable. RESULTS: The odds of experiencing 30-day mortality and morbidity were significantly less in the statin-pretreated group, with unadjusted odds ratios of 0.43 (95% confidence interval [CI], 0.28-0.66) and 0.72 (95% CI, 0.61-0.86), respectively. Risk-adjusted odds ratios for mortality and morbidity were 0.55 (95% CI, 0.32-0.93) and 0.76 (95% CI, 0.62-0.94), respectively, by using a logistic regression model and 0.51 (95% CI, 0.27-0.94) and 0.71 (95% CI, 0.55-0.92), respectively, in the propensity-matched model, demonstrating significant reductions in 30-day morbidity and mortality. In a subsample of patients undergoing valve-only surgery (n = 716), fewer valve-only patients treated with statins experienced mortality, although these results were not statistically significant (1.96% vs 7.5%). CONCLUSIONS: These findings indicate that statin pretreatment before cardiac surgery confers a protective effect with respect to postoperative outcomes.

Cardiac Surgical Procedures↗
PubMed2006

Real-time three-dimensional echocardiography is useful in the evaluation of patients with atrioventricular septal defects.

OBJECTIVE: We sought to determine whether three-dimensional echocardiography (3DE) is useful in the evaluation of patients with atrioventricular septal defect (AVSD). BACKGROUND: Recent advances in 3DE have enhanced its practicality. We assessed whether 3DE provided new information compared to 2DE among patients with AVSD. METHODS: We retrospectively reviewed 52 3DE datasets from 51 patients (median age: 4.6 years, range 0-30 years; median BSA: 0.6 m2, range 0.2-1.9 m2) with any type of AVSD during a 1-year period. 3DE findings were compared to 2DE and surgical reports. For each study, AVSD was classified by 2DE as one of the following: unrepaired balanced defect, repaired balanced defect with residual lesions, repaired balanced defect without residual lesions, or unbalanced defect. 3DE was graded as (1) Additive: 3DE resulted in a new finding or changed diagnosis; (2) Useful: While useful, 3DE did not result in new findings or changed diagnosis; or (3) Not useful. RESULTS: 3DE on unrepaired balanced AVSD and repaired AVSD with residual lesions was more often additive/useful (33/36; 92%) than on repaired AVSD without residual lesions or unbalanced AVSD (9/16 (56%), P=0.009). 3DE was additive or useful in all three patients with unbalanced AVSD being considered for biventricular repair. Useful information obtained by 3DE included: precise characterization of mitral regurgitation and cleft leaflet, substrate for subaortic stenosis, valve anatomy, and presence and location of additional septal defects. CONCLUSION: 3DE provides useful and additive information in unrepaired balanced AVSD, repaired AVSD with residual lesions, and unbalanced AVSD under consideration for biventricular repair.

Adolescent↗
PubMed2006

Cardiac transplantation in South Carolina: 300 transplants.

For nearly 20 years, the Medical University's Heart Transplant Program has been providing the citizens of South Carolina with excellent results with a minimum of delay. We present here the results of our first 300 heart transplants, spanning the first 18 years of the Cardiac Transplant Program at the Medical University. Overall survival has been very good, with one, five and ten year survival rates in the adults being 92 +/- 2%, 78 +/- 3%, and 58 +/- 4%. The children's group showed survival rates of 94 +/- 5%, 79 +/- 11%, and 79 +/- 11% over the same lengths of time. Most recently, the federally sponsored Scientific Registry of Transplant Recipients (www.ustransplant.org, July 2005) reports for MUSC a one-year survival of 97.67% and three-year survival of 90.74%; both leading the Southeast. We attribute this success to the dedicated work of health care workers at all levels who believe in attention to detail and that the patient always comes first. It is our hope that we will be able to continue to provide expert, state-of-the-art, cardiac transplant services long into the future, while continuing to expand our heart failure management program as dictated by further developments in this rapidly evolving specialty.

Adolescent↗
PubMed2006

Prevention of thrombosis and embolism in children and adolescents with mechanical valve prostheses: warfarin versus antiplatelet agents.

BACKGROUND AND AIM OF THE STUDY: Postoperative thromboembolic complications associated with mechanical valve prosthesis implantation can be reduced with either antiplatelet agents or warfarin. Warfarin been shown to be more effective in adults, but the data are less clear in the pediatric population. METHODS: Seventy-two children and adolescents who survived mechanical valve implantation on the left side of the heart at the authors' institution were followed prospectively from August 1979 until December 2003. All patients underwent surgery before the age of 20 years, and follow up was included up to the age of 20 years. Initially, 53 patients received warfarin alone; mean follow up was 5.9 years, and total follow up 312 patient-years (pt-yr). Likewise, 19 patients received antiplatelet agents; mean follow up was 5.2 years, and total follow up 99 pt-yr. Results were examined using intent-to-treat analyses. RESULTS: Age, gender, race, valve size and position, mean time of follow up and crossover rates were not different between groups. No differences were detected in survival or freedom from thromboembolic and hemorrhagic events. Complications associated with warfarin use were substantially more severe than those associated with antiplatelet agents. CONCLUSION: The study results were inconclusive due to the small numbers of patient-years of follow up, but suggest that antiplatelet agents may be associated with less severe complications than warfarin. Moreover, warfarin and antiplatelet agents may be equally effective for clotting prophylaxis in children after valve replacement with St. Jude Medical prostheses.

Adolescent↗
PubMed2006

Valve surgery in renal dialysis patients.

BACKGROUND AND AIM OF THE STUDY: Mechanical valves are used in dialysis patients due to the presumed rapid degeneration of tissue valves. The study aim was to compare the results of mechanical and tissue valves placed in renal dialysis patients. METHODS: Information obtained from a computer-based valve replacement database, telephone interviews and patient charts was reviewed for follow up data. RESULTS: Between 1991 and 2004, 50 dialysis patients underwent left-sided valve replacement. Of these patients, 17 received 21 St. Jude Medical mechanical valves (12 aortic, nine mitral), and 33 received 39 tissue valves (19 aortic, 20 mitral). The mean follow up for the mechanical and tissue valve groups was 19.4 +/- 21.3 and 21.4 +/- 18.7 months, respectively. Mortality at four years was 65% (11/17) for the mechanical valve group, and 42% (14/33) for the tissue valve group (p = 0.15). Freedom from reoperation was not significantly different. The tissue valve group had significantly higher Kaplan-Meier freedom from thromboembolism (100% versus 75 +/- 15%, p = 0.01), hemorrhage (97 +/- 3% versus 44 +/- 17%, p = 0.002), valve-related morbidity (74 +/- 9% versus 42 +/- 16%, p = 0.043), and valve-related morbidity and mortality (69 +/- 9% versus 37 +/- 14%, p = 0.037) at three years. Linearized rates of hemorrhage (21 versus 2%/pt-yr; p = 0.005), valve-related morbidity (36 versus 12%/pt-yr; p = 0.02) and valve-related morbidity and mortality (50 versus 17%/pt-yr; p = 0.008) were all significantly higher in the mechanical valve group. CONCLUSION: Dialysis patients had poor survival; prosthetic valve degeneration was negligible. Incidences of thromboembolism, bleeding and valve-related morbidity and mortality were higher with mechanical valves. Linearized, as opposed to actuarial, analysis further accentuated the unacceptably high rates of complications and death with mechanical valves.

Bioprosthesis↗
PubMed2005

Thoracic surgery education--past, present, and future.

Organized thoracic surgery education began with the establishment of the first thoracic residency program at the University of Michigan in 1928. Subsequent changes and progress in thoracic education have included the development of the American Board of Thoracic Surgery, the Thoracic Surgery Residency Review Committee, the Thoracic Surgery Directors' Association, the Matching Program, the In-Training Examination, and the Joint Council on Thoracic Surgery Education. Current challenges in thoracic surgery education include (1) the declining interest in medical school and especially in surgery and cardiothoracic surgery, (2) changing demographics of medical students and residents, (3) lifestyle of surgical residents and practicing surgeons, (4) changes in societal expectation, and (5) the need for better tools to assess the outcomes of surgical education and the continued competency of practicing surgeons. Despite the recent difficulty with job availability for finishing cardiothoracic residents, there is evidence that this is temporary and that there will be an increased need in the future. Recent changes by the American Board of Thoracic Surgery, including making optional American Board of Surgery certification, new pathways for entry into the cardiothoracic surgery educational process, and the recent development of a joint training proposal (4/3) by the American Board of Surgery and American Board of Thoracic Surgery, clearly signal the need for further changes in the cardiothoracic surgery educational process so that thoracic surgery remains relevant in the future care of patients with cardiovascular disease.

Decision Making↗
PubMed2005

Sustained ventricular tachycardia following alcohol septal ablation for hypertrophic obstructive cardiomyopathy.

A 49-year-old man with a history of hypertrophic obstructive cardiomyopathy (HOCM) presented in sustained monomorphic ventricular tachycardia (SMVT) 8 days post-alcohol septal ablation. A dual chamber implantable cardioverter defibrillator ICD was implanted and the patient experienced another episode of VT 3 weeks later, which was terminated by an ICD shock. This case demonstrates probable scar-induced reentrant VT post-alcohol septal ablation, a likely rare but hypothesized complication of this procedure.

Cardiomyopathy, Hypertrophic↗
PubMed2004

Efficacy of transthoracic cardioversion of atrial fibrillation using a biphasic, truncated exponential shock waveform at variable initial shock energies.

Biphasic shocks are more effective than damped sine wave monophasic shocks for transthoracic cardioversion (CV) of atrial fibrillation (AF), but the optimal protocol for CV with biphasic shocks has not been defined. We conducted a prospective, randomized study of 120 consecutive patients with persistent AF to delineate the dose-response curve for CV of AF with a biphasic truncated exponential shock waveform and to identify clinical predictors of shock efficacy. Our data suggest that the initial shock energy for CV with this waveform should be 200 J if the patient weighs <90 kg and 360 J if the patient weighs >/=90 kg.

Aged↗
PubMed2004

Papaverine delivery to the internal mammary artery pedicle effectively treats spasm.

BACKGROUND: Left internal mammary artery spasm is well recognized during coronary artery bypass operations. Papaverine has been used by many surgeons to maximize mammary artery flow perioperatively, but the best delivery method is not known. We analyzed two techniques used at our institution. METHODS: Fifty-eight patients were randomized into three groups to compare papaverine's ability to prevent spasm and to treat established spasm. Group 1 was control and no treatment was employed. In group 2, papaverine was injected with a blunt needle through the endothoracic fascia parallel to the mammary artery before harvest to assess spasm prevention. In group 3, papaverine was delivered perivascular in an identical manner to group 2 but after the mammary artery was dissected from the chest wall. This group was an evaluation of spasm treatment. Drug dosage was the same for both groups and routine bypass grafting was performed. Before anastomosing the mammary artery to the left anterior descending artery, blood flow was recorded for 15 seconds and flow per minute calculated. Cardiopulmonary bypass pressures were maintained at 70 mm Hg during collection. RESULTS: Mean blood flows were: group 1 = 86.2 mL/min, group 2 = 122.5 mL/min, and group 3 = 139.7 mL/min. Left internal mammary artery flow in group 3 was statistically different from control (p = 0.0457). Group 2 flow approached but did not reach statistical significance (p = 0.0874). Mammary artery dissection times for the three groups were not different. CONCLUSIONS: Papaverine delivery to the left internal mammary artery after dissection treats spasm effectively, improves blood flow at the time of its anastamosis to the left anterior descending artery, and avoids any risk of intimal injury. Injection of papaverine before mammary artery harvest does not shorten dissection time, and flow is not statistically improved.

Arterial Occlusive Diseases↗
PubMed2004

Valve-sparing aortic root replacement: experience at MUSC.

Approximately 30 to 40 percent of patients requiring aortic root replacement have a normal or repairable aortic valve. At the Medical University of South Carolina Medical Center, 12 patients have recently undergone aortic root replacement using a valve sparing technique to preserve the native valve and avoid the potential complications of mechanical or bioprosthetic tissue valves. The early results are excellent and support the use of this procedure for aortic root replacement in the presence of an anatomically normal aortic valve.

Adolescent↗
PubMed2003

Twenty-year experience with the St Jude Medical mechanical valve prosthesis.

BACKGROUND: We have prospectively followed all adult St Jude Medical mechanical valve recipients at the Medical University of South Carolina since the initial implant in January 1979 and now present our 20-year experience. METHODS: We prospectively followed 837 valve recipients (aortic valve replacement; n = 478; mitral valve replacement; n = 359) from January 1979 to December 2000 at 12-month intervals. RESULTS: Ages ranged from 19 to 84 years. Follow-up averaged (mean +/- standard deviation) 7 +/- 5 years (98% complete). Patients were in New York Heart Association class III or IV in 77% (aortic valve replacement) and 89% (mitral valve replacement) preoperatively. A 19-mm valve was implanted in 15.5% of aortic valve replacement patients. Coronary bypass was required in 31% of aortic valve replacements and 20% of mitral valve replacements. Operative mortality was 17/478 (3.6%) in aortic valve replacement and 19/359 (5.3%) in mitral valve replacement, and multivariable predictors were 19-mm valve size, 3 or more coronary bypass grafts, and New York Heart Association class IV for aortic valve replacement and New York Heart Association class IV and age for mitral valve replacement. Actuarial survivorship at 10 and 20 years was 57% +/- 3% and 26% +/- 5% for aortic valve replacement and 61% +/- 3% and 39% +/- 4% for mitral valve replacement. Multivariable predictors of late death were African-American ethnicity, New York Heart Association class III or IV, coronary bypass, and age for aortic valve replacement and New York Heart Association class III or IV, coronary bypass, and age for mitral valve replacement. For aortic valve replacement, effective orifice area was univariately (P =.002) but not multivariately (P =.378) predictive of late death. Structural valve deterioration was not observed. For aortic valve replacement, actuarial freedom (at 10 and 20 years) from reoperation was 93% +/- 1% and 90% +/- 2%; thromboembolism, 82% +/- 3% and 68% +/- 8%; bleeding events, 77% +/- 3% and 66% +/- 6%; prosthetic valve endocarditis, 94% +/- 1% and 94% +/- 1%; valve-related mortality, 94% +/- 2% and 86% +/- 4%; and valve-related mortality or morbidity, 58% +/- 3% and 32% +/- 8%. For mitral valve replacement, actuarial freedom (at 10 and 20 years) from reoperation was 96% +/- 1% and 90% +/- 3%; thromboembolism, 77% +/- 3% and 59% +/- 7%; bleeding events, 86% +/- 2% and 65% +/- 8%; prosthetic valve endocarditis, 98% +/- 1% and 96% +/- 2%; valve-related mortality, 89% +/- 0.2% and 74% +/- 8%; and valve-related mortality or morbidity, 63% +/- 3% and 29% +/- 7%. CONCLUSIONS: After 2 decades of observation with close follow-up, the St Jude Medical mechanical valve continues to be a reliable prosthesis.

Actuarial Analysis↗
PubMed2003

Pharmacologic inhibition of intracellular caspases after myocardial infarction attenuates left ventricular remodeling: a potentially novel pathway.

OBJECTIVE: Myocyte death occurs by necrosis and caspase-mediated apoptosis in the setting of myocardial infarction. In vitro studies suggest that caspase activation within myocytes causes contractile protein degradation without inducing cell death. Thus, caspase activation may evoke left ventricular remodeling through 2 independent processes post-myocardial infarction. However, the effects of caspase activation on left ventricular geometry post-myocardial infarction remain unclear. This project applied broad-spectrum caspase inhibition to a chronic porcine model of myocardial infarction. METHODS: Coronary snares and sonomicrometry crystals in remote and area-at-risk regions were placed in pigs (n = 22, 34 kg). Geometric measurements at end diastole and end systole, including left ventricular area by echocardiography and interregional distance by sonomicrometry, were obtained at baseline. Coronary occlusion was instituted for 60 minutes, followed by reperfusion and repeated geometric measurements at 7 days, including left ventriculography. At reperfusion, pigs were randomized to saline (n = 12) or caspase inhibition (n = 10, IDN6734, 2 mg/kg intravenously, then 2 mg x kg x h for 24 hours) at a dose that achieved desired plasma concentrations (790 +/- 142 ng/mL) as predicted by prior pharmacokinetic studies. RESULTS: Infarct size and 24-hour troponin-I values were not significantly different between the saline and caspase inhibition groups (51% +/- 8% vs 42% +/- 6% and 189 +/- 20 ng/mL vs 152 +/- 26 ng/mL, respectively, P >.10). At 7 days, end-diastole volume was increased in both groups compared with reference control values (47 +/- 1 mL, P <.05), but it was decreased with caspase inhibition (72 +/- 4 mL) compared with saline (84 +/- 4 mL, P <.05). Similarly, end-diastole and end-systole areas increased by 32% +/- 3% and 81% +/- 16% in the saline group but were attenuated with caspase inhibition (19% +/- 3% and 31% +/- 10%, respectively, P <.05). End-diastole interregional distance increased by 30% +/- 7% in the saline group but was attenuated with caspase inhibition (12% +/- 5%, P <.05). CONCLUSION: Despite equivalent degrees of myocardial injury, caspase inhibition reduced post-myocardial infarction left ventricular remodeling as evidenced by multiple, independent assessments of left ventricular dilation. Thus, caspase activation alters left ventricular geometry in the absence of significant effects on myocardial injury.

Animals↗
PubMed2003

Modulation of calcium transport improves myocardial contractility and enzyme profiles after prolonged ischemia-reperfusion.

BACKGROUND: Ischemia-reperfusion (IR) injury causes myocardial dysfunction in part through intracellular calcium overload. A recently described pharmacologic compound, MCC-135 (5-methyl-2-[1-piperazinyl] benzenesulfonic acid monohydrate, Mitsubishi Pharma Corporation), alters intracellular calcium levels. This project tested the hypothesis that MCC-135 would influence regional myocardial contractility when administered at reperfusion and after a prolonged period of ischemia. METHODS: A circumflex snare and sonomicrometry crystals within remote and area-at-risk regions were placed in pigs (n = 18, 32 kg). Coronary occlusion was instituted for 120 minutes followed by 180 minutes of reperfusion. At 105 minutes of ischemia pigs were randomly assigned to IR only (n = 11) or MCC-135 (IR-MCC [300 microg. kg(-1). h(-1), n = 7]) administered intravenously. Regional myocardial contractility was determined by calculation of the regional end-systolic pressure-dimension relation (RESPDR [mm Hg/cm]). Myocardial injury was determined by measurement of plasma levels of myocyte-specific enzymes. RESULTS: At 90 minutes ischemia, mean troponin-I was 35 +/- 8 ng/mL with no significant difference between groups. At 180 minutes reperfusion, heart rate was increased by 18% +/- 5% in the IR only group (p < 0.05) and was reduced by 11% +/- 4% with IR-MCC (p < 0.05). At 90 minutes ischemia RESPDR was reduced from baseline by 51% +/- 6% (p < 0.05). By 30 minutes reperfusion, reductions in RESPDR were attenuated with IR-MCC compared with IR only values. The CK-MB levels were increased at 180 minutes reperfusion in the IR only group (52 +/- 9 ng/mL) compared with baseline (6 +/- 1 ng/mL, p < 0.05) but were attenuated with IR-MCC (24 +/- 4 ng/mL, p < 0.05) compared with IR only values. CONCLUSIONS: Despite similar degrees of injury at 90 minutes ischemia MCC-135 improved regional contractility and reduced the egress of CK-MB. Moreover MCC-135 was associated with decreased heart rate, a determinant of myocardial oxygen demand. Pharmacologic modulation of calcium transport ameliorates myocardial dysfunction in the acute IR period.

Animals↗
PubMed2003

Matrix metalloproteinase inhibition modifies left ventricular remodeling after myocardial infarction in pigs.

BACKGROUND: Global and regional shape changes that occur within the left ventricular wall after myocardial infarction have been termed infarct expansion. A potential mechanism for this postinfarction remodeling is activation of the matrix metalloproteinases. Accordingly, the present study examined the effects of matrix metalloproteinase inhibition on left ventricular global geometry after myocardial infarction in pigs. METHODS: Myocardial infarction was created in pigs by means of occlusion of the first and second obtuse marginal branches of the circumflex coronary artery, resulting in a uniform left ventricular free wall infarct size of 21% +/- 2%. At 5 days after infarction, the pigs were randomized to undergo broad-spectrum matrix metalloproteinase inhibition (n = 9; PD166793, 20 mg. kg(-1). d(-1) by mouth) or myocardial infarction alone (n = 8). Ten pigs served as noninfarction control animals. Left ventricular end-diastolic area, determined by means of echocardiography, was measured 8 weeks after infarction. RESULTS: Left ventricular end-diastolic area increased in both the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition and myocardial infarction only groups compared to reference control animals (3.7 +/- 0.2 cm(2)), but was reduced with broad-spectrum matrix metalloproteinase inhibition compared to myocardial infarction alone (4.5 +/- 0.2 vs 4.9 +/- 0.2 cm(2), respectively; P <.05). Regional radial stress within the infarct region increased in both infarction groups when compared to values obtained from reference control animals (599 +/- 152 g/cm(2)), but was attenuated in the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition group compared to the myocardial infarction alone group (663 +/- 108 vs 1242 +/- 251 g/cm(2), respectively; P <.05). Similarly, regional myocardial stiffness increased in both the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition and the myocardial infarction only groups compared with that observed in reference control animals (14 +/- 1 rkm, P <.05) but was lower with broad-spectrum matrix metalloproteinase inhibition than with myocardial infarction alone (42 +/- 6 vs 68 +/- 10 rkm, respectively; P <.05). CONCLUSIONS: Matrix metalloproteinase inhibition reduced postinfarction left ventricular dilation, reduced regional myocardial wall stress, and modified myocardial material properties. These unique findings suggest that increased myocardial matrix metalloproteinase activation after infarction contributes directly to the left ventricular remodeling process.

Analysis of Variance↗