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Biomedical subjects

K B Allen

Publications and source records attributed to K B Allen.

At least 19 recordsLinked to original sources
PubMed1999

Comparison of transmyocardial revascularization with medical therapy in patients with refractory angina.

BACKGROUND: Transmyocardial revascularization involves the creation of channels in the myocardium with a laser to relieve angina. We compared the safety and efficacy of transmyocardial revascularization performed with a holmium laser with those of medical therapy in patients with refractory class IV angina (according to the criteria of the Canadian Cardiovascular Society). METHODS: In a prospective study conducted between March 1996 and July 1998 at 18 centers, 275 patients with medically refractory class IV angina and coronary disease that could not be treated with percutaneous or surgical revascularization were randomly assigned to receive transmyocardial revascularization followed by continued medical therapy (132 patients) or medical therapy alone (143 patients). RESULTS: After one year of follow-up, 76 percent of the patients who had undergone transmyocardial revascularization had improvement in angina (a reduction of two or more classes), as compared with 32 percent of the patients who received medical therapy alone (P<0.001). Kaplan-Meier survival estimates at one year (based on an intention-to-treat analysis) were similar for the patients assigned to undergo transmyocardial revascularization and those assigned to receive medical therapy alone (84 percent and 89 percent, respectively; P=0.23). At one year, the patients in the transmyocardial-revascularization group had a significantly higher rate of survival free of cardiac events (54 percent, vs. 31 percent in the medical-therapy group; P<0.001), a significantly higher rate of freedom from treatment failure (73 percent vs. 47 percent, P<0.001), and a significantly higher rate of freedom from cardiac-related rehospitalization (61 percent vs. 33 percent, P<0.001). Exercise tolerance and quality-of-life scores were also significantly higher in the transmyocardial-revascularization group than in the medical-therapy group (exercise tolerance, 5.0 MET [metabolic equivalent] vs. 3.9 MET; P=0.05); quality-of-life score, 21 vs. 12; P=0.003). However, there were no differences in myocardial perfusion between the two groups, as assessed by thallium scanning. CONCLUSIONS: Patients with refractory angina who underwent transmyocardial revascularization and received continued medical therapy, as compared with similar patients who received medical therapy alone, had a significantly better outcome with respect to improvement in angina, survival free of cardiac events, freedom from treatment failure, and freedom from cardiac-related rehospitalization.

Aged↗
PubMed1999

Cardiac sympathetic denervation after transmyocardial laser revascularization.

BACKGROUND: Transmyocardial laser revascularization (TMR) has been shown to improve refractory angina not amenable to conventional coronary interventions. However, the mechanism of action remains controversial, because improved myocardial perfusion has not been consistently demonstrated. We hypothesized that TMR relieves angina by causing myocardial sympathetic denervation. METHODS AND RESULTS: PET imaging of resting and stress myocardial perfusion with [13N]ammonia (NH3) and of sympathetic innervation with [11C]hydroxyephedrine (HED) was performed before and after TMR in 8 patients with class IV angina ineligible for CABG or PTCA. A mean of 50+/-11 channels were created in the left ventricle (LV) with a holmium:YAG laser. A semiautomated program was used to determine NH3 uptake and HED retention in the LV. Perfusion and innervation defects were defined as the percentage of LV with tracer uptake or retention >2 SD below normal mean values. All patients experienced improvement in their angina by 2.4+/-0.5 angina classes after surgery, P=0.008. Sympathetic innervation defects exceeded resting perfusion defects in all patients before TMR (34.6+/-27.3% for HED versus 9.4+/-10.8% for NH3, P=0.008). TMR did not significantly affect resting or stress myocardial perfusion but increased the extent of sympathetic denervation in 6 of 8 patients by 27.5+/-15.9%, P=0.03. In the remaining 2 patients, both sympathetic denervation and stress perfusion defects decreased after surgery. CONCLUSIONS: TMR causes decreased myocardial HED uptake in most patients without significant change in resting or stress myocardial perfusion, suggesting that the improvement in angina may be at least in part due to sympathetic denervation.

Aged↗
PubMed1999

Pericardial effusion: subxiphoid pericardiostomy versus percutaneous catheter drainage.

BACKGROUND: Optimal management of cardiac tamponade resulting from pericardial effusion remains controversial. METHODS: Cardiac tamponade in 117 patients was treated with either subxiphoid pericardiostomy (n = 94) or percutaneous catheter drainage (n = 23). Percutaneous catheter drainage was used for patients with hemodynamic instability that precluded subxiphoid pericardiostomy. Effusions were malignant in 75 (64%) of 117 patients and benign in 42 (36%) of 117. RESULTS: Subxiphoid pericardiostomy had no operative deaths and a complication rate of 1.1% (1 of 94). In contrast, percutaneous drainage had significantly (p < 0.05) higher mortality and complication rates of 4% (1 of 23) and 17% (4 of 23), respectively. Patients with an underlying malignancy had a median survival of 2.2 months, with a 1-year actuarial survival rate of 13.8%. In comparison, patients with benign disease had a median survival of 42.8 months and a 1-, 2-, and 4-year actuarial survival rate of 79%, 73%, and 49%, respectively (p < 0.05). Effusions recurred in 1 (1.1%) of 94 patients after subxiphoid pericardiostomy compared with 7 (30.4%) of 23 patients with percutaneous drainage (p < 0.0001). CONCLUSIONS: Benign and malignant pericardial tamponade can be safely and effectively managed with subxiphoid pericardiostomy. Percutaneous catheter drainage should be reserved for patients with hemodynamic instability.

Cardiac Tamponade↗
PubMed1998

Transmyocardial revascularization in patients with refractory, unstable angina.

BACKGROUND: Previous reports of transmyocardial revascularization (TMR) indicate a significant mortality in patients with refractory, unstable angina. We hypothesized that TMR with a holmium laser would result in significant angina relief with acceptable mortality in this patient population. METHODS AND RESULTS: Patients were defined as unstable if they were unweanable from intravenous antianginal medications or were too unstable for a persantine thallium scan. Patients had a left ventricular ejection fraction (LVEF) of > 25% and were not amenable to CABG or PTCA. Before treatment, all patients had class IV angina. TMR was performed in 85 patients, with a mean of 35 +/- 11 transmural laser channels. Mean age was 63 +/- 10 years. Mean LVEF was 48 +/- 11%. Of these patients, 79% were men. Prior CABG and/or PTCA had been performed in 87% of patients, and 72% of patients had a history of prior MI. Operative mortality was 12% (10 of 85). There were 2 deaths between discharge and 3 months after surgery and 7 late deaths from 6 to 12 months after surgery. Twelve-month mortality was 22.4% (19 of 85). At 3 months, 86% of patients had class II angina or better. At 6 and 12 months, 77% and 75% of patients, respectively, had class II angina or better. Mean angina class at 6 and 12 months' follow-up was 1.5 +/- 1.1 and 1.6 +/- 1.3, respectively. CONCLUSIONS: In patients with refractory unstable angina, TMR with a holmium laser provided significant angina relief. Moreover, 30-day operative mortality and 12-month mortality were acceptable, especially given this subset of unstable patients with refractory angina.

Aged↗
PubMed1998

Endoscopic versus traditional saphenous vein harvesting: a prospective, randomized trial.

BACKGROUND: Saphenous vein harvested with a traditional longitudinal technique often results in leg wound complications. An alternative endoscopic harvest technique may decrease these complications. METHODS: One hundred twelve patients scheduled for elective coronary artery bypass grafting were prospectively randomized to have vein harvested using either an endoscopic (group A, n = 54) or traditional technique (group B, n = 58). Groups A and B, respectively, were similar with regard to length of vein harvested (41 +/- 8 cm versus 40 +/- 14 cm), bypasses done (4.1 +/- 1.1 versus 4.2 +/- 1.4), age, preoperative risk stratification, and risks for wound complication (diabetes, sex, obesity, preoperative anemia, hypoalbuminemia, and peripheral vascular disease). RESULTS: Leg wound complications were significantly (p < or = 0.02) reduced in group A (4% [2 of 51] versus 19% [11 of 58]). Univariate analysis identified traditional incision (p < or = 0.02) and diabetes (p < or = 0.05) as wound complication risk factors. Multiple logistic regression analysis identified only the traditional harvest technique as a risk factor for leg wound complications with no significant interaction between harvest technique and any preoperative risk factor (p < or = 0.03). Harvest rate (0.9 +/- 0.4 cm/min versus 1.2 +/- 0.5 cm/min) was slower for group A (p < or = 0.02) and conversion from endoscopic to a traditional harvest occurred in 5.6% (3 of 54) of patients. CONCLUSIONS: In a prospective, randomized trial, saphenous vein harvested endoscopically was associated with fewer wound complications than the traditional longitudinal method.

Age Factors↗
PubMed1998

Transmyocardial revascularization utilizing a holmium:YAG laser.

OBJECTIVE: To evaluate the efficacy of transmyocardial revascularization performed on patients with refractory class IV or unstable angina with a holmium:yttrium-aluminum-garnet laser. METHODS: Transmyocardial revascularization with a holmium:yttrium-aluminum-garnet laser was performed in 42 patients with refractory angina who were not candidates for percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. Patients had either Canadian Heart Association class IV angina (n = 23) or unstable angina (n = 19) and were unable to be weaned from intravenous nitroglycerin. Preoperative thallium studies identified the extent and location of reversible ischemia. Operative exposure was via a limited left anterior thoracotomy. An average of 45+/-11 laser channels were created with a mean operative time of 106+/-38 min. RESULTS: Perioperative mortality was 12% (5/42) with no late deaths. Complications included ventricular 7.1% (3/42) and atrial 4.7% (2/42) arrhythmias, reoperation for chest-wall hemorrhage 2% (1/42), and respiratory failure requiring reintubation 2% (1/42). Intra-aortic balloon pump placement was required in 12% (5/42). The mean postoperative length of stay was 5.5+/-4.9 (1-25) days. Mean follow-up on 100% of patients is 5.4+/-3.0 (1-12) months. At 3 (n = 33) and 6 (n = 21) months follow-up the mean angina class was 1.5+/-0.1 (P < 0.002) and 1.1+/-0.1 (P < 0.001), respectively. CONCLUSIONS: Transmyocardial revascularization utilizing a holmium:yttrium-aluminum-garnet laser resulted in a significant reduction in angina class and was beneficial in patients with refractory angina untreatable by conventional methods.

Angina Pectoris↗
PubMed1997

Endoscopic saphenous vein harvesting.

Although the use of arterial conduit has decreased the amount of saphenous vein required for routine coronary artery bypass grafting, the saphenous vein as a bypass conduit remains an essential component of most practices. We describe the technique of endoscopic vein harvest that, in our initial experience with 30 patients, has improved patient satisfaction and decreased the complications associated with traditional harvest techniques.

Aged↗
PubMed1997

Minimally invasive versus conventional reoperative coronary artery bypass.

BACKGROUND: Conventional reoperative (redo) coronary artery bypass grafting (CABG) is associated with significant morbidity. This retrospective study compared perioperative outcomes of conventional single-vessel redo CABG versus redo CABG done by a minimally invasive technique. METHODS: Group A consisted of 23 consecutive patients from September 1995 to July 1996 who underwent single vessel redo CABG of the left anterior descending artery with the left internal mammary artery using a limited anterior thoracotomy without cardiopulmonary bypass; group B consisted of 12 consecutive patients from November 1984 to July 1994 who underwent the same procedure using a median sternotomy with cardiopulmonary bypass. The two groups were similar with regard to age, sex, preoperative ejection fraction, and risk stratification. RESULTS: Mortality, cerebrovascular accidents, myocardial infarctions, and reoperations for bleeding were not significantly different between the groups. However, the patients in group A had significant reductions in atrial fibrillation, time to extubation, transfusions required, and length of cardiac recovery and hospital stay. With a mean of 12 +/- 6 months of follow-up, 87% of the patients in group A (20 of 23) are alive and asymptomatic. Actuarial survival rates for the patients in group B at 1, 2, and 10 years are 83%, 83%, and 72%, respectively. CONCLUSIONS: Minimally invasive single-vessel redo CABG can be performed safely and may reduce the morbidity associated with conventional single-vessel redo CABG.

Actuarial Analysis↗
PubMed1995

Subxiphoid pericardial drainage for pericardial tamponade.

As a result of recent reports and enthusiasm for video-assisted thorascopic pericardiectomy, we reviewed our experience with subxiphoid pericardial drainage. From August 15, 1988, to June 7, 1993, 155 patients underwent subxiphoid pericardial drainage for pericardial effusion associated with pericardial tamponade. The group comprised 85 female (55%) and 70 male patients whose ages ranged from 5 weeks to 88 years. The procedure was carried out with general anesthesia in 113 patients (72%) and with local anesthesia and sedation in 42 patients. Underlying cancer was present in 82 patients; 73 patients had benign disease. Follow-up is complete in all patients. The overall 30-day mortality was 20%; in patients with cancer it was 32.9% (27/82) versus 5.4% (4/73) for patients with benign disease. No postoperative death was attributed to the surgical procedure. Recurrent pericardial tamponade necessitating further surgical intervention occurred in four patients (2.5%), two with cancer (2.4%) and two with benign disease (2.7%). Median survival after subxiphoid pericardial drainage in patients with benign disease was more than 800 days versus 83 days in patients with cancer (p < 0.01). Median survival after pericardial drainage in patients with cancer who had malignant pericardial effusion was 56 days compared with 105 days for patients with cancer who did not have tumor in the pericardium (p < 0.05). We believe that subxiphoid drainage is the procedure of choice for patients with pericardial tamponade. It is accomplished quickly, is associated with minimal morbidity, and prevents recurrent tamponade in 97.4% (151/155) of patients.

Adolescent↗
PubMed1994

Transhiatal stapled esophagojejunostomy without a pursestring suture in patients with previous gastric resection.

Previous gastric resection complicates alimentary tract reconstruction after esophagectomy. Colonic interposition is the standard conduit in this circumstance, but has substantial mortality and morbidity, especially important when treatment goals are to provide effective alimentation and minimize hospital stay. This report details the technique of a transabdominal, intrathoracic, stapled esophagojejunostomy created without a pursestring suture, which was used to reconstruct the esophagus in 3 patients who had previously undergone partial gastrectomy. This technique avoids both colon interposition and thoracotomy, thereby minimizing the associated complications.

Aged↗
PubMed1994

Malignant pleural mesothelioma. Extrapleural pneumonectomy and pleurectomy.

Diffuse malignant pleural mesothelioma is an uncommon, uniformly fatal malignancy. Controversy continues to surround the optimal surgical procedure, both extrapleural pneumonectomy or pleurectomy, which should be utilized in conjunction with post-operative chemotherapy and/or radiotherapy. This retrospective study reviews a single institution's experience with extrapleural pneumonectomy and pleurectomy in the multimodality treatment of diffuse malignant pleural mesothelioma.

Aged↗
PubMed1992

Surgery for achalasia of the cardia in children: the Dor-Gavriliu procedure.

The Dor-Gavriliu procedure was utilized in six children with achalasia of the cardia from 1983 to 1991. Four boys and two girls (mean age, 10.1 years; range, 3 months to 16 years) presented with symptoms of weight loss (83%), emesis (83%), dysphagia (67%), recurrent respiratory infections (67%), and nocturnal regurgitation (33%). The diagnosis of achalasia was established by barium swallow in all patients; esophageal manometry was used in four patients to confirm the diagnosis. Follow-up ranged from 10 months to 8 years (mean, 3.5 years). Four neurologically normal patients had excellent results with complete resolution of their preoperative symptoms. Two neurologically impaired children, both afflicted with Down's syndrome, had less than excellent results. One moderately impaired child had a good result (required three postoperative bougie dilations over 8 years without demonstration of gastroesophageal reflux); the second, more severely impaired child, had only a fair result (persistent failure to thrive with the development of grade II gastroesophageal reflux). The Dor-Gavriliu procedure uses a transabdominal, anterior esophageal myotomy with incorporation of an effective, nonobstructing, antireflux mechanism that should prevent myotomy reapposition.

Adolescent↗
PubMed1992

Wandering spleen: anatomic and radiologic considerations.

Wandering spleen is a rare clinical entity and remains an elusive clinical diagnosis, particularly in the pediatric patient. Among the imaging modalities (computerized tomography, magnetic resonance imaging, nuclear medicine, ultrasonography, plain films) used in the diagnosis of wandering spleen, ultrasonography is the least invasive and most effective. Elective splenopexy remains the treatment of choice when the diagnosis is made before splenic infarction. We present two cases of wandering spleen manifested as a lower abdominal mass, and we discuss the surgical anatomy of the spleen and splenic ligaments and the hypothetical responsibility of these ligaments for the genesis of this clinical entity.

Adolescent↗
PubMed1992

Isolated splenic metastasis from rectal carcinoma.

Splenic metastasis is a late manifestation of disseminated disease. Focal metastatic splenic involvement, however, without evidence of additional systemic disease, is unique. Review of the literature yielded only one case of isolated splenic metastasis incidental to rectal carcinoma. We have reported an additional case of isolated solitary splenic metastasis from primary adenocarcinoma of the rectum. Theoretically, certain anatomic, histologic, and functional splenic attributes may limit splenic involvement from metastatic disease.

Adenocarcinoma↗
PubMed1992

Acute mesenteric ischemia after cardiopulmonary bypass.

Acute mesenteric ischemia is an uncommon but catastrophic event after cardiopulmonary bypass. From 1980 to 1990, 16,951 cardiac procedures requiring cardiopulmonary bypass were performed at Emory University Hospital in Atlanta, Ga. Eighteen patients (0.1%) had acute mesenteric ischemia that resulted in intestinal infarction. Emergency cardiac surgery had been performed in 16 of the 18 patients, and all 18 patients were vasopressor dependent for hemodynamic support after surgery. Diagnostic difficulties resulted in the diagnosis of intestinal infarction an average of 9 1/2 days after cardiopulmonary bypass. Nonocclusive mesenteric arterial ischemia was the determined cause in all cases. Statistically significant risk factors associated with acute mesenteric ischemia after cardiopulmonary bypass surgery included (1) emergency cardiac surgery (p less than 0.0001), (2) the use of an intraaortic balloon pump (p less than 0.0001), (3) failed angioplasty requiring emergency surgery (p = 0.0074), (4) prolonged pump time (p = 0.0093), and (5) advanced age (p = 0.0016). A high index of suspicion for mesenteric ischemia after cardiopulmonary bypass in patients with identified risk factors may decrease the diagnostic delay and lead to an improvement in the 67% mortality rate seen in this series.

Age Factors↗
PubMed1991

Spontaneous pneumoperitoneum. A surgical dilemma.

Pneumoperitoneum is usually the result of hollow viscus perforation with associated peritonitis. Nonsurgical spontaneous pneumoperitoneum incidental to intrathoracic, intra-abdominal, gynecologic, iatrogenic, and other miscellaneous causes not associated with perforated viscus have been documented in the literature. Seven cases of spontaneous pneumoperitoneum admitted over 3-year period to Grady Memorial Hospital, Atlanta, Georgia are reported. Six patients with pneumoperitoneum underwent exploratory laparotomy when clinical examination suggested an acute abdomen; no intra-abdominal pathology was documented in any of these patients. A seventh patient, on ventilatory support, was managed conservatively after performing a diagnostic peritoneal lavage that was negative. There were no cases of radiographically misdiagnosed pneumoperitoneum. Pneumoperitoneum, preceded by a reasonable incidental cause in a patient with a adequate abdominal examination, may warrant continued observation thus avoiding an unnecessary laparotomy.

Adult↗