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Biomedical subjects

J C Baldwin

Publications and source records attributed to J C Baldwin.

At least 37 records · Page 2Linked to original sources
PubMed1998

Operation for acute and chronic aortic dissection: recent outcome with regard to neurologic deficit and early death.

BACKGROUND: We reviewed our experience in the repair of acute and chronic aortic dissection with regard to early neurologic deficit and death. METHODS: Between February 1991 and June 1996, we performed 206 operations on 195 patients for aortic dissection. Ascending or arch repair, or a combination (type A dissection) was performed on 92 of 206 patients (45%); 44 of 92 (48%) were acute dissection and 48 of 92 (52%) were chronic. Descending or thoracoabdominal repair (type B dissection) was performed on 114 of 206 patients (55%); 22 of 114 (19%) were acute and 92 of 114 (81%) were chronic. RESULTS: Among type A cases, strokes occurred in 6 of 92 patients (7%) overall; 4 of 44 (9%) were acute cases and 2 of 48 (4%) were chronic (p < 0.34). Early deaths for type A were 11 of 92 (12%) overall; 9 of 44 (20%) acute and 2 of 48 (4%) chronic (p < 0.02). In type B cases, neurologic complications were 15 of 114 (13%) overall; 7 of 22 (32%) were acute cases and 8 of 92 (9%) were chronic (p < 0.004). Early deaths for type B were 12 of 114 (11%) overall; 3 of 22 (14%) acute and 9 of 92 (10%) chronic (p < 0.6). Preoperative hypotension was significant in acute type A patients, with strokes in 2 of 7 (29%) hypotensives compared with 2 of 37 (5%) normotensives (p < 0.05) and early death in 4 of 7 (57%) hypotensives versus 5 of 37 (14%) normotensives (p < 0.009). CONCLUSIONS: Morbidity and mortality for repair of chronic dissection types A and B were acceptable. Preoperative hypotension in acute type A dissection was a major predisposing factor toward stroke (29% versus 5%, p < 0.05). Acute type B dissection had acceptable mortality (14%) but a high rate of neurologic complications (32%).

Acute Disease↗
PubMed1998

Effect of extended cross-clamp time during thoracoabdominal aortic aneurysm repair.

BACKGROUND: In previous studies of the neurologic outcome of patients undergoing thoracoabdominal aortic aneurysm repair with the simple cross-clamp technique, cross-clamp time of greater than 30 minutes was identified as an important risk factor. We retrospectively examined the effect of clamp time of 30 minutes or greater on outcome for patients undergoing repair with the addition of surgical adjuncts. METHODS: Between February 1991 and June 1996 we operated on 370 patients for thoracoabdominal or descending thoracic aortic aneurysm. Two hundred seventy-one of these patients with cross-clamp times of 30 minutes or greater were included in this study. One hundred twelve patients underwent simple cross-clamp repair, whereas 159 were operated on with the surgical adjuncts of distal aortic perfusion and cerebrospinal fluid drainage. RESULTS: By multivariate analysis, acute dissection, surgical adjuncts, and aneurysm extent proved most significant in overall patient outcome. The overall rate of early neurologic deficits was 23 of 271 (8.5%). For highest risk patients with type II thoracoabdominal aortic aneurysms, the rate of neurologic deficits was 11 of 29 (38%) for cross-clamp versus 6 of 82 (7.3%) for adjunct operation patients (odds ratio = 0.13; p < 0.001). CONCLUSIONS: The adjuncts of cerebrospinal fluid drainage and distal aortic perfusion decreased the risk of extended cross-clamp time during thoracoabdominal aortic aneurysm repair, particularly for highest risk type II.

Aged↗
PubMed1998

Importance of intercostal artery reattachment during thoracoabdominal aortic aneurysm repair.

PURPOSE: We studied the relationship of neurologic deficit to ligation, reimplantation, and preexisting occlusion of intercostal arteries to determine which arteries and consequent management are most critical to outcome in thoracoabdominal aortic aneurysm repair. METHODS: From February 1991 to July 1996, 343 patients with thoracoabdominal aortic aneurysms underwent repair by one surgeon. In this study, only Crawford types I, II, and III (n = 264) were considered. Of these, 110 (42%) were type I, 116 (44%) type II, and 38 (14%) type III. The adjuncts of distal aortic perfusion and cerebrospinal fluid drainage were used in 164 patients (62%). Data were analyzed by contingency table and by multiple logistic regression. RESULTS: Early neurologic deficit occurred in 23 patients (8.7%), and late deficit in 10 patients (3.8%). Neurologic deficit in patients with at least one reimplantation and no ligation of arteries T11 or T12 occurred in 19 of 147 (12.9%). Neurologic deficit for occlusion of the same arteries occurred in 11 of 111 (9.9%), whereas for ligation of T11 and T12 neurologic deficit occurred in three of six (50%; reimplantation, p < 0.03; occlusion, p < 0.006). In addition, reimplantation of intercostal arteries T9 or T10 was significantly associated with reduced late neurologic deficit in multivariate analysis (p = 0.05). No other intercostal artery status was associated with modification of the neurologic deficit rate. Multivariate analysis showed type II aneurysms and acute dissections to be significantly associated with an increased risk of postoperative neurologic deficit (p < 0.0009, 0.002, respectively). Adjuncts were protective (p < 0.007), most often in types II and III (14.1% neurologic deficit in type II with adjunct, 35.3% without; 0% in type III with adjunct, 20% without). CONCLUSION: Patients with patent arteries at the T11/T12 level have highly variable outcomes depending on whether the arteries are reattached or ligated. Our data suggest that reimplantation of thoracic intercostal arteries T11 and T12 is indicated when these arteries are patent. Reimplantation of T9 and T10 lowers the risk of late neurologic deficit, probably by decreasing the spinal cord's vulnerability to changes in blood and cerebrospinal fluid pressure in the days after surgery. Adjuncts lower overall risk and provide adequate time for targeted intercostal artery reimplantation.

Adolescent↗
PubMed1998

Mitral valve injury from blunt trauma.

Mitral valve injury from blunt trauma to the chest is an uncommon entity. We report a case of mitral valve injury after a fall, and its repair. The English literature is reviewed from the earliest report in 1873 to the present. The diagnosis, types of injury and surgical correction are discussed.

Accidental Falls↗
PubMed1997

Impact of retrograde cerebral perfusion on ascending aortic and arch aneurysm repair.

PURPOSE: The effect of retrograde cerebral perfusion on the incidence of stroke and death among patients undergoing repair of aneurysms of the ascending aorta and transverse arch was determined. MATERIALS AND METHODS: Between January 1991 and March 1995, 161 patients were operated on for aneurysms of the ascending aorta and transverse arch. Thirty-three of the patients (20%) had an aneurysm of the ascending aorta only and 128 (80%) had aneurysms of both the ascending aorta and the transverse arch. All the patients underwent cardiopulmonary bypass, profound hypothermia, and circulatory arrest, and 120 (74%) also underwent retrograde cerebral perfusion. Median pump time was 143 minutes (range, 21 to 461 minutes). Median circulatory arrest time was 42 minutes (range, 8 to 111 minutes), and median myocardial ischemic time was 71 minutes (range, 14 to 306 minutes). RESULTS: The overall 30-day mortality rate was 6% (9 patients) and the incidence of stroke was 4% (7 patients). The use of retrograde cerebral perfusion demonstrated a protective effect against stroke (3 of 120 patients, or 3%) compared with no retrograde cerebral perfusion (4 of 41 patients, or 9%; odds ratio, 0.24; confidence interval, 0.06 to 0.99; p < 0.049). This was most significant in patients more than 70 years of age; none of the 36 elderly patients who received retrograde cerebral perfusion had a stroke, compared with 3 of the 13 (23%) who did not (p < 0.003). Only pump time was associated with an increased risk of stroke (odds ratio, 1.01; 95% confidence interval, 1.00 to 1.02; p < 0.005). Pump time also was associated with increased mortality (odds ratio, 1.01; 95% confidence interval, 1.00 to 1.02; p < 0.008). CONCLUSION: Retrograde cerebral perfusion decreased the incidence of stroke in patients undergoing repair of aneurysms of the ascending aorta and transverse arch.

Adult↗
PubMed1997

Ischemic left ventricular free wall rupture: prediction, diagnosis, and treatment.

Left ventricular free wall rupture is the third leading complication and the second most common cause of death after myocardial infarction. Its occurrence has been considered an unpredictable event usually leading to death. An increased appreciation for the clinical presentation of this syndrome and the nearly ubiquitous use of echocardiography have fostered a rise in the antemortem diagnosis of left ventricular free wall rupture, allowing the possibility of operative repair. Despite the increased reporting of left ventricular free wall rupture, the experience of any one surgeon or surgical group tends to be quite small. We review the current status of rupture prediction, clinical presentation, diagnosis, and treatment options. A recent case of left ventricular free wall rupture referred to the Baylor Cardiothoracic Surgery Group with the misdiagnosis of ruptured dissection of the ascending thoracic aorta is presented to illustrate our approach to this clinical situation.

Heart Rupture, Post-Infarction↗
PubMed1997

CT reconstruction of an unusual chronic posttraumatic aneurysm of the thoracic aorta.

Chronic traumatic aneurysm of the thoracic aorta is an unusual occurrence. Previously, arteriography was performed on all patients seen in our institution with this entity to allow confirmation of the diagnosis and anatomic delineation for operation. A case of chronic traumatic aneurysm of the distal descending aorta discovered on a routine chest roentgenogram and evaluated with chest computed tomographic scanning with three-dimensional reconstruction is presented. It is our belief that not all thoracic aneurysms require arteriography, and improved methods of computed tomographic scanning allow adequate diagnosis and anatomic delineation with decreased morbidity and cost.

Accidents, Traffic↗
PubMed1997

Staged repair of extensive aortic aneurysm: improved neurologic outcome.

OBJECTIVE: We reviewed the adjuncts for brain and spinal cord protection and modifications of operative techniques. SUMMARY BACKGROUND DATA: Two-staged repair--the "elephant trunk" technique--has provided the means for successful repair of massive aortic aneurysms, although historically morbidity has been high. METHODS: Between February 1991 and February 1996, we operated on 512 patients for thoracic aortic aneurysm. Preoperative, intraoperative, or postoperative predictors of morbid outcomes were studied in 63 patients treated with the elephant trunk technique. Data were analyzed by contingency table methods. RESULTS: After stage 1, there were no strokes among patients who received retrograde cerebral perfusion (0 of 53), two strokes occurred among patients who did not receive retrograde cerebral perfusion (2 of 10 [20%]), and early mortality occurred in 4 of the 63 patients (6%). Interval mortality occurred in 6 of 59 patients (10%); 3 (50%) of these 6 deaths were due to distal aortic aneurysm rupture. Thirty-eight patients have undergone stage two repair thus far. There was no incidence of neurologic deficit after stage 2, and early mortality occurred in 1 of the 38 patients (3%). CONCLUSIONS: Extensive aortic aneurysm can be successfully treated using the elephant trunk technique. In this group of patients, retrograde cerebral perfusion eliminated neurologic complications.

Adult↗
PubMed1997

Acute management of complex cardiac injuries.

BACKGROUND: Injury to the heart has been studied extensively. However, a small group of patients with injuries to the coronary arteries or intracardiac structures may require a different operative approach. METHODS: Retrospective review of a cardiovascular injury database. RESULTS: Over a 20-year period, 711 cardiac injuries were treated. The mean age of the victims was 31.1 (90% men). Causes were primarily stab wounds (54%) and gunshot wounds (42%). Cardiac chambers injured included the right ventricle (40%), left ventricle (40%), right atrium (24%), and left atrium (3%). The overall mortality was 47%. Sixty complex injuries occurred. Of 21 left anterior descending coronary artery injuries (76.2% mortality), two patients presented with sufficient signs of life to warrant emergent coronary artery bypass (mortality 50%). There were seven circumflex/obtuse marginal coronary artery injuries, all treated with ligation (mortality 71.4%). Eight right/posterior descending coronary artery injuries (mortality 62.5%) were seen, and all but one were treated with ligation. The one patient not treated with ligation underwent coronary bypass and died. Delayed mitral valve replacement was performed for two valvular injuries (mitral). There were a total of 14 intracardiac fistulas (mortality 35.7%). All six of the surviving patients with ventricular septal defect required reoperation. CONCLUSION: The mortality for complex injuries (coronary, septal, valvular) was 53%. This group was a specific population that self-selected by surviving to operation. Acute operations for complex injuries (beyond cardiorrhaphy) were primarily heroic life-saving efforts. Reoperation for cardiac injuries was most common for septal or valvular injuries. Only 2% of all survivors required reoperation to correct a residual defect.

Acute Disease↗
PubMed1997

Coronary artery bypass conduits: review of current status.

Coronary artery bypass grafting (CABG) is the most common procedure performed in adult cardiovascular surgery today. In our Department of Surgery at Baylor College of Medicine, we have experienced, as have most large programs, a trend to older patients, more comorbidity, worse ventricular function, and more redo CABG procedures. Along with this shift has come an evolution in surgical techniques, cardioplegia and choice of coronary bypass graft conduits. The benefit of using an internal mammary artery (IMA) to the left anterior descending coronary artery (LAD) appears irrefutable at this time. Data for multiple arterial grafts is still evolving and conduit choice for other than the IMA to LAD graft is often debated. The purpose of this article is to review the current literature on conduit choice and to allow a rational, data driven approach to graft choice.

Adult↗
PubMed1996

Cerebrospinal fluid drainage and distal aortic perfusion: reducing neurologic complications in repair of thoracoabdominal aortic aneurysm types I and II.

PURPOSE: This study was conducted to evaluate the role of cerebrospinal fluid (CSF) drainage and distal aortic perfusion (DAP) in the prevention of postoperative neurologic complications for high-risk patients who had undergone type I and type II thoracoabdominal aortic aneurysm (TAAA) repair. METHODS: CSF drainage and DAP were used as an adjunct in the treatment of 94 patients with TAAA (31 type I, 63 type II) between September 1992 and December 1994; 67 were men and 27 were women. The median age was 64 years (range, 28 to 88 years). Aortic dissection occurred in 35 of 94 patients (37%). Thirty-six of 94 patients (38%) had previously undergone proximal aortic surgery. All patients underwent intraoperative DAP and perioperative CSF drainage. Median aortic cross-clamp time was 67 minutes (range, 20 to 131 minutes). RESULTS: The 30-day survival rate was 90% (85 of 94 patients). Early neurologic complications occurred in 5 of 94 patients (5%), and late neurologic complications occurred in 3 of 94 patients (3%). We compared the neurologic complications of our current group of 94 patients with the data from 42 patients (control group) who also underwent repair of TAAA type I and type II with only simple cross-clamp and without CSF drainage or DAP. Both groups were treated by the senior author (HJS) at the same institution. Total neurologic complications for the current group occurred in 8 of 94 patients (9%) versus 8 of 42 patients (19%) for the control group (p=0.090). Neurologic complications for patients with type II TAAA occurred in 8 of 63 patients (13%) versus 17 of 42 patients (41%) (p=0.014). For all patients with aortic clamp times >or=45 minutes, neurologic complications occurred in 7 of 55 (13%) versus 7 of 18 (39%) (p=0.033). CONCLUSION: The period of risk during aortic cross-clamp time is reduced with the adjuncts of CSF drainage and DAP, which significantly lower the incidence of neurologic complications after repair of TAAA types I and II.

Adult↗
PubMed1996

Autoregulation of myocardial glycogen concentration during intermittent hypoxia.

During hypoxia, the heart consumes glycogen to generate ATP. Tolerance of repetitive hypoxia logically requires prompt replenishment of glycogen, a process whose regulation is not fully understood. To examine this, we imposed a defined hypoxic stimulus on the rat heart while varying its workload. In intact rats, hypoxia reduced myocardial glycogen approximately 30% and increased both the fraction of glycogen synthase in its physiologically active (GS I) form (from 0.24 +/- 0.06 to 0.82 +/- 0.07; P < 0.005) and glycogen synthesis (from 0.087 +/- 0.011 to 0.375 +/- 0.046 mumol.g-1.min-1; P < 0.005). Reducing cardiac work (with propranolol or heterotopic transplantation) reduced glycogen breakdown, glycogen synthase activation, and glycogen synthesis in parallel, stepwise fashion in intact rats. Correspondingly, hypoxia increased GS I activity in the perfused heart in vitro, but only under conditions where glycogen was consumed. This suggests myocardial glycogen synthase is activated by systemic hypoxia and catalyzes rapid posthypoxic glycogen synthesis. Hypoxic glycogen synthase activation appears to be a proportionate, wholly intrinsic response to local glycogenolysis, operating to preserve myocardial glycogen stores independent of any extracardiac mediator of carbohydrate metabolism.

Animals↗
PubMed1996

Left ventricular rupture following mitral valve replacement.

Left ventricular rupture following mitral valve replacement is an unusual and often lethal complication. Despite being well described since the initial description in 1967 by Roberts, this catastrophic complication still occurs. A recent case of a delayed Type III rupture is presented. The pathology and repair of the three recognized types of rupture are reviewed and the preventive measures discussed.

Aged↗
PubMed1995

Optimal timing of coronary artery bypass graft surgery after acute myocardial infarction.

BACKGROUND: To assess optimal timing for coronary artery bypass graft surgery (CABG) after an acute myocardial infarction (AMI), all patients undergoing CABG without associated procedures at our institution from January 1, 1991, to July 30, 1992, were reviewed. Patients were divided into three groups based on time from infarct to revascularization. The control group consisted of patients operated on for angina refractory to medical management. Relative risks (incident infarction group divided by incident control group) were established for need of vasopressors, new balloon to separate from bypass, perioperative myocardial infarction, and hospital mortality. METHODS AND RESULTS: One hundred sixteen patients underwent CABG within 6 weeks of infarction. In the experimental group, 58 patients underwent CABG for non-Q-wave infarction, and 58 patients underwent CABG for Q-wave infarction. In the control group, 255 patients underwent surgery for angina without infarction. Patients were analyzed by group relative to the time between infarction and CABG. Patients were analyzed between infarction and CABG and assigned to one of three groups. Group 1 patients were revascularized within 48 hours; group 2, between 3 and 5 days; and group 3, after 5 days. Significance was determined by Fisher's exact or Mantel-Haenszel chi 2 test where appropriate. Multivariate analysis was performed on statistics that were significant. All patients within all groups after Q-wave or non-Q-wave myocardial infarction had a significantly higher risk of needing an intra-aortic balloon pump and vasopressors to be weaned from bypass and a greater incidence of perioperative MI compared with control patients. Surgical mortality is highest immediately after Q-wave infarctions. CONCLUSIONS: Patients with non-Q-wave infarction may undergo CABG relatively safely at any time. Acceptable timing for CABG after Q-wave infarction is after 48 hours.

Aged↗
PubMed1995

Effect of nonworking heterotopic transplantation on rat heart glycogen metabolism.

To determine whether the contractile work history of cardiac muscle influences its responsiveness to insulin, we examined the effect of insulin infusion on glycogen metabolism in the rat heart 1 wk after transplantation into a nonworking heterotopic infrarenal position. Nonworking heterografts had higher basal glycogen concentrations than did in situ working hearts of the same animals (29.9 +/- 2.7 vs. 23.3 +/- 0.8 mumol/g; P < 0.05), and a smaller fraction of their glycogen synthase enzyme activity was in the physiologically active glycogen synthase I form (8 +/- 2 vs. 22 +/- 3%; P < 0.02). During a 25-min infusion of insulin (1 U/min) and glucose (30 mg.kg-1.min-1), the fractional glycogen synthase I activity of heterografts remained lower than that of in situ hearts (29 +/- 5 vs. 56 +/- 7%; P < 0.02) and heterografts synthesized glycogen more slowly (0.126 +/- 0.07 vs. 0.352 +/- 0.06 mumol.g-1.min-1; P < 0.02). These effects could be duplicated by a 24-h fast, which similarly increased myocardial glycogen concentration (to 32.9 +/- 5.6 mumol/g). These observations suggest that the performance of repetitive contractile work is necessary to maintain the myocardium maximally responsive to insulin. Mechanical unloading increases myocardial glycogen concentration, thereby reducing the magnitude of insulin's stimulation of glycogen synthase and consequently the rate of incorporation of circulating glucose into glycogen.

Animals↗
PubMed1995

Use of neodymium yttrium aluminum garnet laser in long-term palliation of airway obstruction.

Palliation of acute airway obstruction using the neodymium yttrium aluminum garnet (Nd-YAG) laser was studied in 54 patients who presented over a 42-month period to the Yale cardiothoracic surgery service. Thirty-seven patients had bronchogenic carcinoma; 27 had stage IIIB or IV disease. Nine patients had endobronchial metastases from a primary nonbronchogenic carcinoma. Eight patients had benign disease. A total of 109 Nd-YAG laser tumor ablations were performed. In addition, 32 patients underwent postoperative brachytherapy. Median survival for all patients was 12 months. Patients with bronchogenic carcinoma had a median survival of five months. Fifteen of 20 patients (75%) alive at the time of follow-up reported continued palliation as shown by an improved postoperative Karnofsky score. There was no survival benefit from Nd-YAG laser ablation of endobronchial bronchogenic carcinoma; however, the Nd-YAG laser provided good to excellent palliation in the majority of patients on long-term follow-up.

Acute Disease↗