PubMed Health⌕ Search

Biomedical subjects

L M Messina

Publications and source records attributed to L M Messina.

69 records · Page 4Linked to original sources
PubMed1990

Artery, periarterial adipose tissue, and blood microbiology during vascular reconstructive surgery: perioperative and early postoperative observations.

The presence and clinical significance of bacteria in the arterial wall, periarterial adipose tissue, and blood samples acquired during elective vascular operations were assessed in this study. Specimens were obtained from a random series of 84 patients (56 men, 28 women) undergoing 75 primary and 9 secondary arterial reconstructions. Operations performed most frequently included abdominal aortic aneurysmectomy (42), aortofemoral bypass reconstruction (15), and lower extremity bypass surgery for occlusive disease (7). Perioperative antibiotics were administered to all but one patient. A sample of artery, adjacent adipose tissue, and blood were obtained for microbial analysis during the vascular anastomosis or arteriotomy. This yielded a total of 152 artery, 139 adipose tissue, and 129 blood samples for study. Each specimen was divided and placed in blood agar plates, thioglycolate broth, and brain-heart infusion broth. Tissues yielding growth of the same organism(s) in two or more different media were considered positive for the presence of bacteria. Bacteria were present in at least one of the three tissues studied in 32/84 patients (38%). The frequency of positive cultures in primary (29/75, 39%) and secondary procedures (3/9, 33%) were similar. One positive culture site occurred in 26/32 (81%) patients, two positive culture sites existed in 5/32 (16%) patients, and three positive sites were found in 1/22 (3%) patients. Eighteen individual artery (18/152, 12%) and 19 adipose tissue samples (19/139, 14%) harbored bacteria, whereas only two blood cultures were positive (2/129, 2%). Organisms identified included coagulase-negative staphylococci (71%), gamma-streptococci (7%), diphtheroids (7%), Micrococcus (5%), alpha-streptococci (5%), Staphylococcus aureus (2%), and Pseudomonas picketti (2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1989

Renal endarterectomy through the transected aorta: a new technique for combined aortorenal atherosclerosis--a preliminary report.

The optimal surgical management of combined aortic and renal atherosclerosis has not been defined. A modified technique of renal endarterectomy performed through the transected aorta before anastomosis of the aortic prosthesis is presented. The surgical course and early follow-up results of the first 44 consecutive patients treated by this technique are reported. Twenty-three patients (25%) had symptomatic coronary artery disease, 36 patients (82%) had arterial hypertension, and 28 patients (64%) had elevated serum creatinine levels (mean 2.10 mg/dl). Primary indications for operation related to aortic disease in 39 patients (89%) and to poorly controlled hypertension in five patients (11%). Seventy-five renal arteries were revascularized; 11% of these arteries were occluded. Revascularizations were bilateral in 27 patients (61%), involved a solitary kidney in three patients (6%), and were unilateral in 14 patients (32%). Aortobifemoral bypass grafting was performed in 16 patients (36%), aortoiliac bypass was performed in 15 patients (34%), and infrarenal aortic replacement was performed in 11 patients (25%). Postoperative complications developed in 14 patients (32%). There were two postoperative deaths (4%). Nineteen patients had transient increases in serum creatinine levels greater than 0.5 mg/dl. Two patients required postoperative dialysis, neither related to failure of their renal revascularization. There were five late deaths, all as a result of myocardial infarction. Renal function improved in four patients and remained stable in 22 patients. Blood pressure was improved in 64% of patients previously hypertensive. These preliminary results indicate that renal endarterectomy through the transected aorta along with aortic reconstruction is a safe, efficient, and effective means of treating these complex lesions.

Adult↗
PubMed1989

Pseudoaneurysm of the inferior gluteal artery presenting as sciatic nerve compression.

A pseudoaneurysm of the inferior gluteal artery presenting as sciatic nerve compression is reported in a 40-year-old woman. Following a transvaginal needle biopsy for endometriosis, the patient developed left sciatic pain and a nonpulsatile mass palpable in the left buttock thought to represent a pyriformis hematoma. Sequential computed tomographic scans were consistent with this diagnosis. Persistent pain and progression of neurological deficits led to surgical exploration. Posterior exposure of the pyriformis muscle and proximal sciatic nerve revealed a large pseudoaneurysm of the inferior gluteal artery compressing the nerve. A laparotomy was performed and the internal iliac artery was ligated, followed by evacuation of the aneurysm contents and repair of the aneurysm neck via a posterior approach. The patient has remained pain-free with progressive improvement in neurological function after 1 year follow-up. Aneurysms of the gluteal artery are unusual, predominantly occur after significant pelvic trauma, and rarely present as sciatica. Pertinent aspects of the patient history and clinical findings are atypical for discogenic sciatica. Because of the rarity of this entity, preoperative diagnosis is usually not achieved. Angiography or magnetic resonance imaging should be performed in patients with atypical sciatica and a mass in the region of the proximal sciatic nerve, particularly after trauma.

Adult↗
PubMed1989

A prospective study of clinically and endoscopically documented colonic ischemia in 100 patients undergoing aortic reconstructive surgery with aggressive colonic and direct pelvic revascularization, compared with historic controls.

Clinically and endoscopically proved ischemia of the colon complicates elective aortic reconstruction in 1% to 2% and 6% to 7% of cases, respectively. Operative mortality exceeds 60% when transmural infarction occurs. A prospective study of colonic ischemia was undertaken in 100 male patients (mean age, 62.4 +/- 7.9 years) undergoing operation for aortic aneurysms (58) or aortoiliac occlusive disease (42). Conventional aortic surgery was undertaken in 88 patients, and in 12 patients adjunctive procedures to enhance colonic perfusion were performed 14 times, including IMA reimplantation (8), direct bypass to the internal iliac artery (4), and anastomosis of an aortofemoral bypass limb to adjacent common iliac artery (2). Colonoscopy was performed within 24 to 48 hours of aortic reconstruction. Three patients had endoscopic evidence of colonic ischemia. Transmural infarction did not develop in any patient, and bowel resections or diverting colostomies were not necessary. Three patients died, none manifesting colonic ischemia. The 12% utilization of adjunctive procedures to enhance blood flow in the colon was substantially greater than the 4% frequency of an earlier experience from our institution in which nearly half of the 5.7% operative mortality was attributed to colonic infarction. Attention to factors contributing to ischemia of the colon, and more frequent adjunctive revascularization of the colon, may lessen this complication of aortic reconstructive surgery.

Angiography↗
PubMed1986

Middle aortic syndrome. Effectiveness and durability of complex arterial revascularization techniques.

Middle aortic syndrome typically occurs as severe hypertension in young patients who have weak or absent femoral pulses and an abdominal bruit. It results from a diffuse narrowing of the distal thoracic and abdominal aorta, commonly involving the visceral and renal arteries. The clinical presentation, angiographic assessment, and surgical outcome of 10 patients (mean age: 19.5 years) who underwent one-stage revascularization for middle aortic syndrome were reviewed to determine the effectiveness and durability of one-stage revascularization techniques to relieve these complications. All patients were hypertensive (mean blood pressure: 176 mmHg); six (60%) had severe, poorly controlled hypertension, two of whom had previous failed operations for renovascular hypertension and one who presented with malignant hypertension and acute renal failure. Five patients had disabling myocardial insufficiency, only one of whom had documented coronary artery disease. Four patients had intermittent claudication. Aortography showed variable length high-grade midaortic stenosis, nine had visceral artery involvement, and eight had renal artery involvement. All patients underwent one-stage revascularization by a variety of autogenous and prosthetic techniques. The postoperative recovery was uncomplicated in eight of nine patients and was often associated with dramatic reduction in blood pressure. There was a single death from disruption of the thoracic anastomosis in a patient who had diffuse cystic medial necrosis of the aorta. Arterial biopsy in nine patients indicated evidence for both acquired and congenital origins of the midaortic stenosis. Late follow-up evaluation (mean: 4.1 years) showed normal growth and development, preservation of renal function, and relief of myocardial insufficiency in all patients. Seven patients (77%) are cured of their hypertension, and two (23%) have only mild hypertension. These results indicate that one-stage revascularization of patients with middle aortic syndrome can result in effective and durable relief of these severe life-threatening complications.

Adolescent↗
PubMed1985

Regulation of transmural myocardial blood flow.

A major problem in understanding how myocardial blood flow is regulated is the common occurrence of subendocardial ischemia in many diseases, with or without coronary arterial disease. Two commonly held explanatory hypotheses were that high systolic intramyocardial pressures prevented flow to deep but not superficial muscle, or that in diastole tissue pressures were highest subendocardially. Neither hypothesis is tenable today, and the likeliest hypothesis is that retrograde systolic flow from the deeper muscle produces a longer time constant for diastolic flow in deep than in superficial muscle.

Biomechanical Phenomena↗
PubMed1985

Effects of pressure gradients between branches of the left coronary artery on the pressure axis intercept and the shape of steady state circumflex pressure-flow relations in dogs.

When steady state pressure-flow relations are studied in the circumflex coronary artery, pressure gradients develop between it and other branches of the left coronary artery. To assess the effects of these pressure gradients, we compared the pressure axis intercept and shape of steady state circumflex pressure-flow relations in the presence and absence of gradients after autoregulation was abolished, both in the beating heart and during long diastoles in dogs. We used peripheral coronary pressures and radionuclide-labeled microspheres to assess arterial collateral flow. In the beating heart, interarterial pressure gradients reduced the curvature at low circumflex pressures, and overestimated the mean pressure axis intercept by 7.8 mm Hg (P less than 0.05). The results were similar for the pressure-flow relations derived during long diastoles. This overestimation exaggerates the difference between the pressure axis intercept and coronary sinus pressure. The peripheral coronary pressure and microsphere results indicate that these effects are mediated largely by arterial collateral flow.

Animals↗
PubMed1984

The effect of coronary inflow pressure on coronary vascular resistance in the isolated dog heart.

The shape of the coronary arterial pressure-flow relationship results from the interaction of a number of poorly understood physiological factors. Experiments in which coronary inflow and outflow pressures were coupled so that driving pressure was held constant showed that changes in inflow or outflow pressures altered coronary blood flow: coronary vascular resistance varied inversely with changes inflow pressure below 50 mm Hg and with changes in outflow pressure below 80 mm Hg. The magnitude of the influence of inflow pressure on resistance also depended on the fixed level of outflow pressure, the influence being large when the outflow pressure was low, and small when it was high. Inflow and outflow pressures, then, are two physiological factors which are determinants of the shape of the pressure-flow relationship, and their interaction contributes to the degree of curvature found in a particular relationship. These findings suggest that the use of linear regression in the interpretation of pressure-flow relationships results in poor estimation of resistance and zero-flow pressure. Other experiments measuring regional coronary blood flow using radionuclide-labeled microspheres resulted in the same inverse relationship between inflow pressure and resistance, regardless of mural depth, indicating that inflow pressure may influence resistance by distending vessels, rather than by causing sequential cessation of perfusion in successive transmural layers.

Animals↗
PubMed1984

Arterial and venous coronary pressure-flow relations in anesthetized dogs. Evidence for a vascular waterfall in epicardial coronary veins.

The coronary circulation of anesthetized dogs was tested for the presence of vascular waterfalls by manipulating coronary arterial and coronary venous pressures. The left main coronary artery and the coronary sinus were cannulated, and relationships between coronary artery pressure, coronary sinus pressure, and coronary flow were studied. Experiments were conducted during diastolic arrests, under steady state conditions, in the absence of autoregulation. Relations of coronary flow to coronary sinus pressure at constant coronary artery pressure were consistent with the presence of a vascular waterfall in the coronary sinus. When the great cardiac vein was cannulated, relations of great vein flow to great vein pressure at constant coronary artery pressure were consistent with the presence of a vascular waterfall in the great vein, indicating that waterfall behavior can occur in epicardial veins other than the coronary sinus. In dogs on right heart bypass, with the coronary sinus and great vein uncannulated, the relationship between right atrial pressure and coronary sinus pressure showed a waterfall pattern, indicating that the waterfall is not an artifact of venous cannulation. In the right heart bypass experiments, venous waterfall behavior was seen in beating hearts as well as during diastolic arrests. We conclude that a vascular waterfall is present in epicardial coronary veins which can significantly influence coronary blood flow.

Animals↗
PubMed1984

The effects of cardiopulmonary bypass on coronary blood flow in the dog.

The effects of cardiopulmonary bypass on autoregulation, maximum coronary flow, and regional blood flow in the heart were investigated in 25 dogs. A Gregg cannula was inserted into the left main coronary artery, and pressure-flow relations were then measured in the autoregulating state or with vasodilation produced by intracoronary adenosine infusion before, during, and after cardiopulmonary bypass. Seventeen of the dogs had radioactive microspheres injected to investigate regional blood flow changes at the same times. (1) Autoregulation was not present after bypass for at least 3 hours. (2) Blood flow was shifted toward the subendocardium on bypass (increased subendocardial/subepicardial ratio) and tended to return to prebypass distribution following bypass. (3) Blood flow after bypass was not significantly different to the subendocardium and subepicardium. (4) Response to a coronary vasodilator (maximum coronary flow) was significantly affected by cardiopulmonary bypass: blood flow to all layers of the heart could be increased with adenosine after bypass. (5) Global lactate and oxygen metabolism were not adversely affected by bypass. We conclude that cardiopulmonary bypass abolished the normal autoregulation of coronary flow; this may predispose the incompletely revascularized patient to a "coronary steal" syndrome. However, the heart with normal coronary arteries is not underperfused in any layer after bypass. Thus, the bypass technique is not the cause of the subendocardial ischemia that sometimes complicates cardiac operations.

Adenosine↗
PubMed1984

Successful aortic valvotomy for severe congenital valvular aortic stenosis in the newborn infant.

The preoperative evaluation, surgical course, and early follow-up results of 11 newborn infants less than 30 days of age who underwent aortic valvotomy for severe valvular aortic stenosis between 1976 and 1983 were reviewed to determine our current surgical mortality and the early prognosis of these neonates. Ten of the 11 patients had severe congestive heart failure and dyspnea. Preoperative cardiac catheterization and angiography detected features characteristic of congenital aortic valvular stenosis in newborn infants. Emergency aortic valvotomy was performed in all during cardiopulmonary bypass, for which a cold (4 degrees C) blood prime and moderate systemic hypothermia were used. An effort was made to achieve maximal relief of the stenosis without causing aortic insufficiency. Mean cardiopulmonary bypass time was 21 minutes and mean cross-clamp time was 6.4 minutes. There was a single operative death, and there have been no late deaths during a mean follow-up period of 2.2 years. All patients are currently free of heart failure. Four patients underwent postoperative cardiac catheterization for clinical suspicion of severe residual stenosis. However, three had only mild or moderate residual stenosis. The fourth had a large gradient, 70 mm Hg, and has since undergone successful repeat valvotomy. These results indicate that neonates with severe valvular aortic stenosis can undergo valvotomy safely and have a favorable early prognosis. The factors responsible for the low mortality appear to include prompt recognition and diagnosis followed by emergency operation, use of a 4 degree C cold pump prime, brief cross-clamp times, and conservative valvotomy to avoid the development of significant aortic insufficiency.

Aortic Valve↗
PubMed1983

Direct measurement of left ventricular interstitial adenosine.

Characterization of adenosine's role as a regulator of coronary blood flow requires accurate measurement of endogenous adenosine concentration in the left ventricular (LV) interstitial compartment. Existing techniques for determining adenosine in this compartment are indirect, requiring the acceptance of major assumptions before conclusions can be drawn. We describe a new technique utilizing a LV epicardial diffusion well that allows us to make rapid, direct measurement of LV interstitial adenosine concentration, avoiding many problems inherent in existing techniques. Our results show adenosine concentrations of 555 pmol/ml in resting anesthetized dogs, indicating a resting adenosine level well within the vasoactive range. Further experiments using intramyocardial bolus injections of methylene blue dye and [8-14C]adenosine indicate that the epicardial well receives adenosine from a transmural distribution of LV interstitium and not from epicardial sources only. The transmural interstitial adenosine is transported via small lymphatics to the epicardial surface of the heart where diffusion occurs into the epicardial well. We also examined diffusion characteristics of the parietal pericardial membrane and found that the rate constant of adenosine diffusion for this and the visceral pericardium are of the same order of magnitude, indicating that the extensively used standard pericardial superperfusate method probably underestimates cardiac interstitial adenosine concentration by 50% or more. The influence of the parietal pericardium adequately explains why our resting adenosine concentrations using the epicardial well are higher than those recently reported using the standard pericardial superperfusate method.

Adenosine↗
PubMedDate not supplied

Extended iliac exposure from the groin.

Knowledge of iliac artery and inguinal anatomy enables extraperitoneal exposure of the iliac arteries for surgical treatment of unilateral inflow disease. A method is presented for exposing the distal common iliac artery, the iliac bifurcation, and the full length of the external iliac artery by detachment and retraction of the inguinal ligament though a single extended groin incision. The indications for unilateral iliac artery exposure, revascularization, surgical anatomy, and technique of iliofemoral exposure through a single, extended groin incision are presented. Extended iliac exposure through a single, extraperitoneal exposure facilitates all methods of unilateral iliac revascularization and provides access for delivery of endovascular devices.

Aged↗