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Biomedical subjects

F Giron

Publications and source records attributed to F Giron.

At least 19 recordsLinked to original sources

Wound complications of the retroperitoneal approach to the aorta and iliac vessels.

Repeated complaints of postoperative wound pain prompted this review of 113 consecutive vascular operations involving a retroperitoneal approach to the aorta or iliac vessels or both. Flank muscle-splitting incisions (n = 53) had been used to approach the terminal aorta or iliac arteries. Two types of muscle-dividing incisions had also been used: incisions through the eleventh intercostal space (n = 41) to approach the infrarenal aorta; and incisions through the eighth, ninth, or tenth intercostal space with division of the diaphragm (n = 19) to approach the suprarenal aorta. Data on incisional pain, lumbosacral neuritic pain, incisional hernia, and deforming abdominal bulge were culled from the records of follow-up examinations conducted on all patients during periods ranging from 2 to 48 months. Both types of muscle-dividing incisions used to expose the aorta were associated with a 23% (14/60) incidence of abdominal bulge, a 7% (4/60) incidence of incisional hernia, and, more important, a 37% (22/60) incidence of prolonged disabling pain. Thus, although retroperitoneal exposure may be the preferred or the safest approach to certain aortic lesions, its routine use via muscle-dividing incisions is not recommended when the proposed operation can be carried out equally well by the conventional midline transperitoneal approach.

Aorta, Abdominal

Complications of percutaneous intra-aortic balloon pump use in patients with peripheral vascular disease.

Percutaneous intra-aortic balloon pump use may carry an increased risk for patients with peripheral vascular disease. To determine the incidence and types of associated complications, the medical records of 144 patients who underwent a total of 153 percutaneous intra-aortic balloon pump insertions were reviewed. Patients were divided into two groups. Group 1 was composed of 20 patients with a history of peripheral vascular disease. Group 2 was composed of 124 patients without such history; they underwent a total of 133 insertions. Nineteen major complications (12%) occurred, 12 in group 1 (60% of 20 insertions) and seven in group 2 (5% of 133 insertions). Major complications were further classified by their nature: embolic, occlusive, and technical. All three types of complications occurred more frequently in group 1. Embolic complications occurred more frequently in patients with aneurysms and proved the most lethal, with two of six deaths in group 1 resulting from this complication.

Aneurysm

Indirect measurement of systolic blood pressure in the rabbit.

Long-term studies of rabbit blood pressure require a reliable method for repeated blood pressure measurements. Ideally, this method would be simple, noninvasive, and accurate over the range of anticipated blood pressures. To facilitate our own studies of rabbit carotid artery graft patency, we have developed a technique for the indirect measurement of systolic blood pressure in the rabbit that utilizes a photoplethysmograph sensor placed distal to an inflatable air bladder positioned over the central ear artery. We have compared measurements obtained with this method to direct measurements of aortic pressure and found a linear correlation.

Animals

Techniques for experimental rat kidney (and liver) perfusion.

The technique described here allows to perfuse in situ either the left kidney alone, both kidneys or both kidneys and the liver of rats with few operations, without danger of organs damage and with a good control of temperature and pressure. This technique allows a good maintainance of the metabolic activity of the perfused tissues and offers the possibility to collect urine by cannulating the bladder.

Animals

Mesenteric blood flow in patients with diabetic neuropathy.

We examined flow velocities in the superior mesenteric artery and celiac artery in normal controls (group C, n = 11), diabetic patients (group D, n = 8), and diabetic patients with clinically evident autonomic neuropathy (group DN, n = 6) to further define the usefulness of duplex examination in the evaluation of the mesenteric circulation in normal and disease states. By use of a 3 MHz duplex scanner, peak systolic velocity, peak diastolic forward velocity, end-diastolic forward velocity, and peak diastolic reverse velocity were measured in centimeters per second before and after a standardized meal. The vessels' diameters in centimeters were also measured. After the meal peak diastolic reverse velocity disappeared in all patients. The average vessel diameter in the superior mesenteric artery (0.7 cm) and celiac artery (0.8 cm) did not change. Flow velocities in the celiac artery were not significantly altered by the meal. In the control group, peak systolic velocity in the superior mesenteric artery increased 38%, peak diastolic forward velocity rose 66%, and end-diastolic forward velocity increased by 70%. In the diabetic nonneuropathic group the changes were 15%, 98%, and 100%, respectively. These changes were statistically significant (p less than 0.01). On the other hand, the patients with diabetic autonomic neuropathy presenting a picture of gastroparesis did not exhibit the expected increases in postprandial velocities. Moreover, this alteration in blood flow velocity, although similar to that encountered in patients with intestinal angina, did not appear to be due to occlusive arterial disease on the basis of clinical examination and B-mode scanning.

Autonomic Nervous System Diseases

Transaortic endarterectomy of renal visceral artery lesions in association with infrarenal aortic surgery.

The complexity of infrarenal aortic reconstruction increases when bypass grafts to revascularize associated renal and visceral arteries are needed. Lesions in these vessels, however, are usually limited to their aortic orifices and therefore are amenable to retroperitoneal transaortic endarterectomy. A combined infrarenal aortic reconstruction and transaortic endarterectomy of the renal/visceral vessels was used in 18 (16%) of 120 patients undergoing elective infrarenal aortic reconstruction over a 2-year-period. Transaortic endarterectomy was performed primarily for renal preservation in 11 patients with bilateral, high-grade renal artery stenoses and abnormal renal function (serum creatinine greater than or equal to 1.9 mg/dl). In seven patients transaortic endarterectomy was performed as a secondary procedure during the course of complex reconstruction of aneurysmal or occlusive aortic disease. Mean serum creatinine, which was elevated preoperatively in 14 (78%) patients (3.3 mg/dl), decreased significantly after the operation (2.0 mg/dl, p less than 0.01). A single death occurred in the 18 patients undergoing transaortic endarterectomy. Renal function preservation can be achieved by renal revascularization in patients with bilateral renal artery stenoses and decreased renal function. The retroperitoneal approach to aortic reconstruction and the use of transaortic endarterectomy allows correction of most renal/visceral vessel involvement in complex aortic revascularization procedures.

Aorta, Abdominal

The value of computed tomography in the management of symptomatic abdominal aortic aneurysms.

The use of computed tomographic (CT) scanning in the diagnosis of ruptured abdominal aortic aneurysm is controversial because the delay created by the procedure, it has been argued, may increase overall mortality. However, if emergency surgery can be avoided in the medically compromised patient, surgical results may improve. To assess the value of CT scanning, we studied the 1983 to 1988 records of 65 hemodynamically stable patients with abdominal aortic aneurysms, who underwent diagnostic CT scanning for acute abdominal or back pain. Twenty-one patients had a history of severe cardiac, renal, or pulmonary disease. The average duration of the examination was 63 minutes; no episodes of hypotension occurred. Subsequently, 17 of 18 patients with ruptured aneurysms had emergency surgery, with 31% morbidity and 29% mortality. Of 44 patients found to have nonruptured aneurysms, 13 had other causes for their pain, nine were not considered surgical candidates, and 24 had elective aneurysmectomies, with 8% morbidity and 0% mortality. In three patients CT scanning excluded the diagnosis of aneurysm. Additional information provided by CT scanning enhanced the safety of the perioperative management of four patients with rupture and 14 without. In conclusion, the delay imposed by obtaining a preoperative CT scan in patients with possible ruptured aneurysm did not adversely affect patient outcome, and the information obtained from it aided significantly in both preoperative and intraoperative management.

Aorta, Abdominal

Energetic behaviour of mitochondria isolated from rat livers perfused with a perfluorodecalin + N,N-perfluorodiethylcyclohexylamine emulsion.

Rat livers have been perfused with a saline control medium or with a perfluorocarbon emulsion containing perfluorodecalin and N,N-perfluorodiethylcyclohexylamine, and the respiratory rates and transmembrane electrical potentials of mitochondria isolated following perfusion have been evaluated. The results indicate that the perfluorocarbon emulsion used, by providing a good oxygen supply to the perfused liver, allowed to preserve the efficiency of mitochondrial oxidative phosphorylation.

Adenosine Triphosphate

The early and late responses of the arterial wall to graft placement.

The relationship between the early smooth muscle cell proliferative response (SMC-PR) to injury and the later development of myointimal hyperplasia (MIH) complicating arterial bypass grafts remains unclear. In the present study, the early SMC-PR and the later MIH induced by a 2-mm-diameter PTFE graft placed in a rabbit carotid were compared with the response induced by an autogenous artery (AA) graft in the contralateral carotid. The early SMC-PR was measured in the proximal and distal arterial segments 5 days after graft placement by in vivo labeling with [3H]thymidine to determine the DNA specific activity (DNA-SA). The later anastomotic MIH was measured 16 and 32 weeks postgrafting by calculating the intimal/medial ratio. There was a marked and similar increase in the early SMC-PR noted with both the AA and the polytetrafluoroethylene (PTFE) grafts. The distal segments demonstrated a significantly higher DNA-SA when compared to the proximal in both AA- and PTFE-grafted arteries. There was a moderate degree of anastomotic MIH noted in chronic grafts; however, a regression in intimal thickening was observed over time in the AA-grafted arteries, while the distal anastomosis of the PTFE-grafted vessels demonstrated a continuous progression of the MIH process. The early SMC-PR may abate in arteries grafted with autogenous grafts, but there is a persistent proliferative response at the distal anastomosis associated with synthetic grafts.

Animals

Clinical and chemical characterization of an adventitial popliteal cyst.

We present further evidence that adventitial cysts of the popliteal artery are ganglions, based on studies of a lesion found in a 51-year-old man. The cyst was located entirely within the adventitia, lacked a cellular lining, and did not communicate with either the arterial lumen or the synovial space. The contents were gel-like and composed of 1.64 gm of hyaluronic acid and 0.20 gm of protein per dl. This material did not possess boundary-lubricating ability in a test system that slides natural latex rubber against glass. The histologic appearance, chemical composition, and absence of lubricating ability more closely resemble the characteristics of ganglions. These findings suggest that the cyst was not synovial but rather ganglionic in origin.

Exudates and Transudates

An animal model for small-diameter arterial grafts.

A rabbit model was developed to study small-diameter arterial grafts. A total of 158 2-mm-diameter polytetrafluoroethylene (PTFE) grafts and 35 autogenous carotid artery (AA) grafts were interposed in the carotid arteries of New Zealand white rabbits. A pilot study of 16 PTFE grafts used to develop operative and anesthetic techniques had a 20% mortality and 38% early (less than 2 day) thrombosis rate. Subsequent to the pilot study 177 grafts were placed and a 92% postoperative survival with 100% AA graft patency and 93% PTFE graft patency at 2 weeks was observed. AA grafts followed beyond 16 weeks continued to have 100% patency, while PTFE grafts began to show increased failure. Closure was found to be due to the development of anastomotic myointimal hyperplasia.

Animals

The effects of endothelial injury on smooth muscle cell proliferation.

The endothelial injury induced by the placement of a synthetic graft has been implicated as a stimulus for the development of MIH. In this study we compared the degree of EC coverage and the early SMC-PR in the arterial segments proximal and distal to 2 mm diameter PTFE grafts that had been placed in rabbit carotid arteries (n = 49). In vivo labeling with 3H-thymidine and Evans blue was carried out at intervals of 2 to 33 days after grafting. The SMC-PR was measured as the degree of 3H-labeled DNA divided by the total DNA for each segment, and the EC coverage was determined by planimetry of the area of Evans blue exclusion. There was an early rise in the SMC-PR in both arterial segments, but it was more marked in the distal segment (p less than 0.001). There was no correlation between the SMC-PR and the degree of EC coverage in either the proximal (r = 0.25) or the distal segments (r = 0.10). The data suggest that there is a greater SMC-PR at the distal end of an implanted PTFE graft. The degree of endothelial loss and its regrowth does not appear to be an important factor.

Animals

Current status of external counterpulsation.

This article traces the development of external counterpulsation from its beginnings to the present. Initially, counterpulsation was carried out by cannulating the femoral artery. The hemodynamic goals were to reduce the afterload of the left ventricle, and to raise or augment the diastolic pressure. This gave rise to the term "counterpulsation." The intra-aortic balloon is capable of producing these salutary effects because of its proximity to the outlet of the left ventricle. The same hemodynamic effects can be obtained by external counterpulsation. However, one must produce a negative pressure during cardiac systole, and ensure that this is applied to the lower extremities. The only clinical study in which this was done was in the treatment of patients in cardiogenic shock by Soroff and colleagues. The results of the clinical studies reviewed are all suggestive of benefits derived from external counterpulsation in a variety of clinical settings. These studies suggest the following avenues for improvement in the equipment used to carry out external counterpulsation: 1. Inclusion of the vascular bed of the buttocks to be subjected to the external pressures, as advocated by Zheng. 2. Inclusion of a negative pressure blanket, as advocated by Soroff. 3. Further investigation of graded-sequential external counterpulsation, using the buttocks and negative pressure. 4. Application of external counterpulsation earlier in cardiogenic shock and for at least 4 hours in acute myocardial infarction. Our evaluation is that this method has not been studied in a way that demonstrates its full potential. We feel that it is on the threshold of being shown to be useful in all of the clinical settings reviewed, and we hope that the necessary equipment will be created to allow investigators to establish its proper place in our therapeutic armamentarium.

Acute Disease

Renal dysfunction after arteriography.

Acute renal failure has been observed in patients undergoing angiography in which a hypertonic triiodinated contrast medium is used. To ascertain the incidence of renal dysfunction and the clinical risk factors, we did a prospective study in which creatinine clearance was measured before and immediately after 120 arteriographic procedures. Thirty-seven patients (31%) sustained a significant reduction in creatine clearance after arteriography. No specific risk factor could be determined. Our findings, however, indicate that patients with preexisting renal insufficiency or diabetes mellitus are not at a higher risk for sustaining a fall in creatinine clearance after angiography.

Acute Kidney Injury

Variational anatomy of the deep femoral artery.

The deep femoral artery is frequently incorporated in vascular reconstructive procedures in the proximal leg. To study the branching variations of this artery, we dissected 100 legs and then classified the anatomical patterns. The deep femoral artery originates a median distance of 4.4 cm from the inguinal ligament. The origin of the lateral circumflex artery varied greatly. When it branched from the deep femoral, the origin of the lateral circumflex was 1.5 cm (median) from the origin of the deep femoral. The medial circumflex artery originated from the deep femoral in 63% of the specimens. It arose separately from the common femoral and more proximally in 26% of the specimens, branching an average of 2.15 cm (median) above the deep femoral origin. Familiarity with these variations is essential to the vascular surgeon and,therefore, we have included diagrams based on our study as a ready reference.

Female

The expanded polytetrafluoroethylene graft. Three years' experience with 362 grafts.

A total of 362 polytetrafluoroethylene (PTFE) grafts were implanted in patients as vascular substitutes in a variety of vascular reconstructive procedures. A total of 184 were used in femoropopliteal bypass operations. Cumulative patency rates showed 74% patency at the end of the first year of observation and 58% after two and three years. Seventeen grafts were used for femorotibial bypasses, with a cumulative patency rate of 40.4% after one year. Ninety-eight grafts were implanted in the upper or lower extremity to serve as vascular access for hemodialysis. For this group, the cumulative one-year patency rate was 83%. Sixty-three additional grafts were implanted in various other anatomic locations. Based on this experience, the PTFE graft seems to be a promising and versatile vascular prosthesis, although it should be used cautiously.

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