PubMed Health⌕ Search

Biomedical subjects

L A Gray

Publications and source records attributed to L A Gray.

At least 19 recordsLinked to original sources
PubMed1996

Left ventricular contributions to right ventricular systolic function during LVAD support.

BACKGROUND: In patients with postcardiotomy low cardiac output syndromes, right ventricular (RV) failure develops in approximately 25% of patients receiving left ventricular (LV) assist device support. Depressed RV function have been attributed to abnormalities of the RV myocardium, excessive load imposed on the RV during systole or diastole, or obstruction to RV inflow. However, recent studies also suggest that LV function may significantly affect RV function through ventricular interdependence. METHODS: We reviewed the data showing the importance of systolic ventricular interaction. We then related these observations to the RV response during LV assist device support, and present our ideas regarding the mechanisms responsible for this RV failure. RESULTS: Using an electrically isolated right heart preparation, Damiano observed double-peaked waveforms for RV pressure, and pulmonary artery blood flow occurred over a wide range (0 to 300 ms) of pacing intervals between the LV and RV. Numeric analysis indicated that RV systolic pressure and pulmonary artery blood flow were composed of both RV and LV components, with the LV component dominating (63.5% versus 36.5%). CONCLUSIONS: The experimental studies indicate a very consistent RV response during LV assist device support: a decrease in RV afterload, increased compliance, and decreased contractility. In normal hearts, the net effect is an increase or no change in cardiac output. With a preexisting pathologic condition, the RV responses is qualitatively the same, but anatomic ventricular interaction is accentuated, leading to a greater decrease in RV contractility. The net effect is a decrease in cardiac output, which may require inotropic or RV mechanical support.

Animals↗
PubMed1995

Feeding kinematics of phyllomedusine tree frogs.

Previous studies have demonstrated that the phyllomedusine hylids possess highly protrusible tongues, a derived characteristic within the family Hylidae. In the present study, the kinematics of the feeding behavior of a phyllomedusine species, Pachymedusa dacnicolor, was analyzed using high-speed video (180 frames s-1). Its behavior was compared with that of Hyla cinerea, a species with a weakly protrusible tongue. P. dacnicolor exhibits a faster rate of tongue protraction, a longer gape cycle and more variable feeding kinematics than H. cinerea. In addition, the tongue is used in a unique 'fly-swatter' fashion, to pin the prey to the substratum as the frog completes the lunge. The rapid tongue protraction, extended gape cycle and fly-swatter action may have evolved in response to a diet of large, rapidly moving insects. In addition, several duration variables of the feeding cycle were greater for misses than for captures and drops, which suggests that sensory feedback rather than biomechanics controls gape cycle duration.

Analog-Digital Conversion↗
PubMed1994

New conduits for coronary artery bypass: great promise for improved outcome from coronary artery surgery.

The internal mammary artery is the conduit of choice for coronary artery bypass, with patency at about 95%, 10 years after implantation. Patients who receive this graft survive longer and have fewer cardiac complications than those who receive only saphenous vein bypass grafts. Surgeons are currently studying other arteries that may be used as bypass conduits. The gastroepiploic artery on the greater curve of the stomach demonstrates the greatest promise, with patency greater than 90% at 3 to 4 years. The radial artery, used in the 1970s but abandoned due to poor results, may be due for a revival, since it has up to 95% patency at one year. The inferior epigastric artery (located posterior to the rectus muscle) is also under consideration, but few results are available. However, it appears that about 80% are patent at one year. The role of these alternative conduits has not yet been clarified in the management of coronary bypass patients. However, these preliminary observations suggest that increased use of these extremely durable bypass conduits may further improve surgical outcomes.

Abdominal Muscles↗
PubMed1993

Postcardiotomy shock: clinical evaluation of the BVS 5000 Biventricular Support System.

This prospective trial evaluated the safety and efficacy of a new pulsatile, temporary ventricular assist device, the BVS 5000. Patients were eligible for treatment if they were hemodynamically unstable despite maximal pharmacologic and intraaortic balloon pump therapy, were free of concomitant complications, and were less than 6 hours from the first attempt to separate from cardiopulmonary bypass. Fifty-five postcardiotomy patients were enrolled; 31 met all selection criteria and the remainder failed to meet criteria (n = 15) or were not successfully supported (n = 9). The BVS 5000 effectively restored hemodynamics: Mean arterial pressure increased (77.1 +/- 8.0 mm Hg on-support versus 50.1 +/- 15.3 mm Hg presupport; p = 0.0001). Cardiac index increased (2.3 +/- 0.3 L.min-1.m-2 on-support versus 1.6 +/- 0.6 L.min-1.m-2 presupport; p = 0.0013). Left ventricular filling pressure decreased (11.9 +/- 4.5 mm Hg on-support versus 23.8 +/- 8.7 mm Hg presupport; p = 0.0030). The most frequent complication was bleeding in 42 patients (76%). Of the patients meeting all criteria, 17 (55%) were weaned from support and 9 (29%) were discharged. Survival was significantly influenced by presupport cardiac arrest events. Survival among patients not experiencing arrest was 47%. Eight patients are long-term survivors and were asymptomatic in New York Heart Association class I or II at 1-year follow-up. The BVS 5000 restored hemodynamics, permitted myocardial recovery, and improved survival in a group of patients who would have otherwise died.

Adult↗
PubMed1993

Retroperitoneal tumors with vena caval extension: a multidisciplinary approach.

In cases of retroperitoneal tumor with extension to the inferior vena cava (IVC), complete resection improves survival, but may require cardiopulmonary bypass (CPB) and hypothermic circulatory arrest (HCA). Since 1985, eight patients at our institution have had complete resection of retroperitoneal tumors with IVC or right atrial involvement. Preoperative evaluation included intravenous pyelography, computed tomography of the chest and abdomen, renal arteriography, and venography or magnetic resonance imaging of the IVC. Operative technique was determined primarily by the extent of IVC or RA involvement and included combined median sternotomy and laparotomy, control of the intrapericardial IVC, and radical tumor resection. IVC tumor thrombectomy was done using either temporary vascular occlusion, CPB, or CPB with HCA. Complete resection for improved survival of retroperitoneal tumors with IVC extension is technically feasible with acceptable morbidity and mortality rates. A multidisciplinary approach allows optimal management of these extensive tumors.

Adrenal Gland Neoplasms↗
PubMed1992

Diagnostic efficacy of endovaginal color Doppler flow imaging in an ectopic pregnancy screening program.

The authors compared the diagnostic yield of endovaginal color and pulsed Doppler ultrasound (US) in conjunction with endovaginal sonography with that of endovaginal sonography alone in patients prescreened to be at increased risk for ectopic pregnancy. Pelvic structures were evaluated for overall vascularity and for the presence of characteristic pulsed Doppler US velocity waveforms. The diagnostic sensitivity of the initial endovaginal sonographic examination increased with the addition of color and pulsed Doppler US, from 71% to 87% for ectopic pregnancy, from 24% to 59% for failed intrauterine pregnancy, and from 90% to 99% for viable intrauterine pregnancy. Specificities for endovaginal sonography with color and pulsed Doppler US ranged from 99% to 100%. Use of endovaginal color and pulsed Doppler US increased the percentage of diagnostic initial sonographic examinations from 62% to 82%. The improved diagnostic sensitivity of endovaginal color Doppler US for ectopic pregnancy may ultimately result in earlier treatment, with reduced morbidity and mortality.

Color↗
PubMed1991

Lateral thoracotomy for the automatic implantable defibrillator.

In 51 patients who required automatic implantable cardioverter defibrillator implantation without additional cardiac procedures, the lead system was implanted using a lateral thoracotomy approach, with complete muscle sparing in the last 24 patients. Exposure was excellent and allowed repositioning of leads for optimal defibrillation thresholds in 18 patients. Five of 19 patients who had previously undergone intrapericardial procedures required intrapericardial dissection for lead placement to provide satisfactory defibrillation thresholds. There were no intraoperative deaths or infarctions. The 30-day mortality rate of 3.9% was comparable with those in other series, and the use of muscle-sparing techniques and supplemental epidural anesthesia prevented pulmonary complications or the need for prolonged ventilatory support. We favor a muscle-sparing lateral thoracotomy incision for automatic implantable cardioverter defibrillator insertion, particularly in patients with a history of previous intrapericardial procedures.

Adult↗
PubMed1991

Emergency aortocoronary bypass after failed angioplasty.

One thousand two hundred fourteen percutaneous transluminal coronary angioplasties were performed over a 38-month period. Sixty patients required immediate emergency coronary artery bypass grafting after angioplasty failure; 7 of these had evidence of acute myocardial infarction before angioplasty and were excluded from the study. Of the 53 patients remaining, 27 (51%) had electrocardiographic and enzyme evidence of postoperative myocardial infarction. Two patients died (4%), and 10 had postoperative complications (19%). No statistical significance was noted comparing age, sex, incidence of prior myocardial infarction or myocardial dysfunction, time for revascularization, or average number of grafts completed in those with single-vessel (n = 21) versus multiple-vessel (n = 32) coronary artery disease. Postoperatively, those with multiple-vessel disease required intraaortic balloon pump support (p = 0.06) and antiarrhythmic medications more frequently than single-vessel patients (p less than 0.01) and had a higher complication rate (p less than 0.05). Although not reaching statistical significance, the data also suggest a higher death and postoperative myocardial infarction rate in patients with multiple-vessel disease. Emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty carries a higher morbidity and mortality than elective coronary artery bypass grafting, particularly for patients with multiple-vessel coronary artery disease.

Aged↗
PubMed1991

Methotrexate treatment of unruptured ectopic pregnancy: a report of 100 cases.

In an ongoing clinical trial, 100 patients with an unruptured ectopic pregnancy of 3.5 cm or less in greatest dimension were treated with an outpatient protocol of methotrexate and citrovorum factor chemotherapy. Methotrexate and citrovorum were given on alternating days until the hCG titer had decreased by 15% on 2 consecutive days. The patients ranged in age from 16-40 years, gravidity from 1-8, and parity from 0-5. Twenty-three patients had a previous ectopic pregnancy. Of the 100 patients, 96 (96%) received methotrexate/citrovorum as primary therapy and four (4%) were treated for persistent hCG titers after a conservative surgical procedure. The tubal pregnancies of patient nos. 1-50 were confirmed by laparoscopy, whereas patient nos. 51-100 were diagnosed according to a nonlaparoscopic algorithm. Four patients of 100 failed medical therapy and required surgery. Of these, one had an ectopic pregnancy with cardiac activity, one ruptured after intercourse, and the remaining two cases had no specific identifiable risk factors. Of the ectopic pregnancies with cardiac activity, 80% were successfully treated. Five patients (5%) had methotrexate-related side effects, all after the fourth dose, but none required treatment for these side effects. Hysterosalpingograms done on 58 patients subsequently demonstrated tubal patency in 84.5% on the involved side. To date, 37 pregnancies have occurred in this group, of which 31 (89.2%) were intrauterine and four (10.8%) were recurrent ectopic pregnancies. We conclude that methotrexate/citrovorum is safe, effective, and helps to preserve reproductive performance when used as primary therapy for unruptured ectopic pregnancy and for treatment of persistent disease following a conservative surgical procedure.

Adolescent↗
PubMed1991

Single-dose methotrexate for treatment of ectopic pregnancy.

Methotrexate treatment of unruptured ectopic pregnancy is safe and effective and preserves reproductive potential. Previous protocols have required multiple methotrexate doses with or without citrovorum rescue. The purpose of this study was to determine whether patients with an unruptured ectopic pregnancy 3.5 cm or less in greatest dimension could be treated with single-dose intramuscular methotrexate (50 mg/m2) without citrovorum rescue. Thirty-one patients were eligible for this outpatient treatment protocol. One patient withdrew from follow-up, leaving 30 patients (96.8%) in the study group. Patients had a mean age of 28.5 years (range 18-37) and a mean gravidity of 3.0 (range 1-8); nine of 30 (30%) had previously undergone a salpingectomy for ectopic pregnancy. Pre-treatment hCG titers ranged from 130-16,700 mIU/mL (mean 4558). Pre-treatment transvaginal sonography visualized the ectopic in 28 of 30 patients (93.3%) and revealed cardiac activity in six patients. Patients were monitored with hCG titers three times per week for the first week, and then weekly until the hCG was less than 15 mIU/mL. A complete blood count and liver enzymes were obtained before treatment and on day 7. All patients had a continued rise in hCG titer for at least 3 days after methotrexate injection, although all levels began to decline by day 7. No patient required a second dose of methotrexate and no patient experienced any side effects. Twenty-nine of 30 patients (96.7%) were successfully treated. Six of 30 (20%) experienced an increase in lower abdominal pain between days 5-10, and two were hospitalized overnight for observation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Management of extensive right ventricular injury or rupture.

Most penetrating right ventricular injuries require simple suture repair, but more extensive injury or rupture of the right ventricle may not be amenable to this method. We have developed an approach to the problem and a technique for repair. Compression of the area with early institution of cardiopulmonary bypass will result in decompression of the right ventricle and preservation of perfusion, preventing profound hypotension. Coverage with an onlay autologous tissue patch provides hemostatic control of the defect without compromising ventricular function. Reinforcement with omentum or muscle flap can give additional protection when risk of infection is present. Application of these principles can be lifesaving and insure good cardiac function despite massive injury to the right ventricular myocardium.

Aged↗
PubMed1990

Extended use of bilateral internal mammary arteries for coronary artery disease.

The internal mammary artery is the conduit of choice for coronary artery revascularization. Wide angulation between the left anterior descending coronary artery and obtuse marginal branches and the diseased segments of the coronary arteries can prevent optimal positioning of the left internal mammary artery for sequential anastomoses for revascularization. We describe a technique using a segment of the left internal mammary artery as a free graft sewn in an end-to-side fashion to the in situ left internal mammary artery. This approach has technical and physiological advantages over previously described techniques.

Coronary Artery Bypass↗
PubMed1990

Surgical approach to atrial septal defect in the female. Right thoracotomy versus sternotomy.

Repair of atrial septal defect (ASD) remains a high-benefit, low-risk procedure due to technologic improvements. From July 1981 to December 1986, 35 females (age, 7 months to 28 years) had repair of ASD; 20 by right thoracotomy and aortic cannulation (group 1) and fifteen by median sternotomy (group 2). In general, right thoracotomy was applied to patients with secundum ASD two years or older and without associated lesions, while median sternotomy was applied to patients with ostium primum lesions and/or associated lesions. Patients or their families perceived the cosmetic results superior to the right thoracotomy approach over the median sternotomy. We feel that a right thoracotomy and aortic cannulation is effective in females (2 years and older) with secundum ASD for a superior cosmetic result over median sternotomy. However, females with ostium primum and/or associated lesions should undergo median sternotomy for better cardiac access and safety.

Adolescent↗
PubMed1989

The Pierce-Donachy ventricular assist device as a bridge to cardiac transplantation.

The Pierce-Donachy ventricular assist device (VAD) was used as an attempted bridge to orthotopic cardiac transplantation in 12 patients aged 13 to 55 years. Ischemic (4 patients), dilated (4 patients), acute viral (1 patient), postpartum (1 patient), and hypertrophic cardiomyopathy (1 patient), along with a failed transplant (1 patient), were the causative factors of end-stage cardiomyopathy in these patients. All patients were candidates for orthotopic cardiac transplantation but sustained refractory cardiogenic shock (cardiac index less than 2 L/min/m2). Left VADs were placed in all patients; 7 also required right VADs. Four patients died of hemorrhagic complications less than 24 hours after VAD insertion. Ventricular assist device stabilization was successful in 8 patients and support ranged from eight hours to 64 days. Seven patients successfully underwent orthotopic cardiac transplantation. One died postoperatively of hemorrhagic complications, 6 were discharged from the hospital, and 1 patient died at 3 months of cytomegalovirus infection. Five patients are long-term survivors. The Pierce-Donachy VAD is an effective means for supporting critically ill patients with end-stage cardiomyopathy and cardiogenic shock before orthotopic cardiac transplantation. Death is related to hemorrhagic, rather than infectious or thromboembolic, complications. Patients successfully stabilized with the VAD can undergo orthotopic cardiac transplantation with acceptable mortality and morbidity rates.

Adolescent↗
PubMed1989

Surgical techniques for the implantation of heterotopic prosthetic ventricles.

Mechanical support of the failing heart is becoming an increasingly useful tool for bridging to cardiac transplantation and for recovery of the natural heart. Several options exist for cannulation sites during the implantation of the heterotopic prosthetic ventricles. These options include the left atrial appendage, the left ventricular apex, the interatrial groove, and the left atrial roof. The indications, contraindications, advantages, disadvantages, and surgical technique for each option are described. Operation of the drive console and postoperative care are also discussed.

Assisted Circulation↗
PubMed1989

Treatment of malignant ventricular arrhythmias with the automatic implantable cardioverter defibrillator.

Twenty-eight patients with malignant ventricular arrhythmias were treated with the automatic implantable cardioverter-defibrillator (AICD) in a 14-month period. Thirteen patients were resuscitated from a ventricular fibrillation (VF) episode. Fifteen patients presented with ventricular tachycardia (VT) refractory to medical therapy. The etiology was coronary artery disease in 23 of 28 patients (82%), dilated cardiomyopathy in 2 of 28 patients (7%), sarcoidosis in 2 of 28 patients, and 1 patient in 28 had lupus erythmatosis. The mean left ventricular ejection fraction was 29%. A total of 27 of 28 patients (96%) patients had inducible ventricular tachycardia using programmed stimulation. The patients considered for AICD implant failed a mean of 3.6 antiarrhythmic drugs. Rate counting and defibrillating leads were inserted through a lateral thoracotomy in 17 patients and a mediansternotomy incision in 11 patients in conjunction with another cardiac procedure in 10 patients. The generators were positioned in a subcutaneous pocket beneath the left costal margin. There were no operative deaths. The mean follow-up was 6.7 months (range 1 to 14) with no VT/VF deaths in patients with defibrillators. The study demonstrated that AICD is an effective device for prevention of sudden cardiac death.

Adult↗
PubMed1989

Otolaryngologic problems in cardiac transplant patients.

Cardiac transplantation is now a well-accepted treatment for selected patients who have end-stage heart disease. Of the 38 patients who underwent cardiac transplants at our center from August 1984 through August 1987, 27 received consultation for otolaryngologic problems. Eleven patients had sinonasal complications; 8 had laryngotracheal complications; 4 had otologic complications; 2 had oropharyngeal complications; and 2 had a combination of more than one of the above complications. Of these otolaryngologic disorders, 63% were infectious in etiology. Development of otolaryngologic infections generally did not correlate with either higher doses of maintenance immunosuppression or with treatment of an acute rejection episode, which requires increased immunosuppression. Otolaryngologists should be aware of the sinonasal, laryngotracheal, oropharyngeal, and otologic disorders that can occur in cardiac transplant patients.

Heart Transplantation↗