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Biomedical subjects

F N Littooy

Publications and source records attributed to F N Littooy.

At least 37 records · Page 2Linked to original sources
PubMed1996

Intensive care after carotid endarterectomy: a prospective evaluation.

BACKGROUND: Through prior investigation we established that only a small minority of patients who undergo carotid endarterectomy (CEA) have a complicated postoperative course requiring an intensive care unit (ICU) stay. An appropriate policy for patient management was established. This study prospectively analyzes the safety and efficacy of this policy. STUDY DESIGN: Patients were transferred directly to a nonmonitored surgical ward, regardless of preoperative comorbidity, if they remained stable from a neurologic and a hemodynamic standpoint during a short (less than three hour) stay in the recovery room. Patients whose status was questionable remained in recovery longer or were transferred to an ICU. RESULTS: One hundred forty-six (79 percent) of 185 patients were transferred safely to a ward. Average length of stay in recovery was one hour 59 minutes. No complications occurred that required a return to the operating suite or a move to an ICU. Most of these patients (88 percent) were discharged within 24 hours of surgery. Thirty-nine (21 percent) patients, each identified in recovery, required intervention or monitoring in an intensive care setting. Fourteen required prolonged, aggressive intravenous treatment of hypertension; 14 had sustained hypotension; three were observed to rule out myocardial infarction, and three had neurologic deficits. Two patients had ventricular arrhythmias, two had wound hematomas, and one patient required reintubation. This group (n = 39) remained in the recovery room two hours 40 minutes on average, spent 20 hours in the ICU, and remained in the hospital 32 hours after CEA. CONCLUSIONS: Most patients who undergo CEA follow a predictably benign postoperative course. Patients are easily identified by a recovery room protocol and approximately 80 percent can avoid ICU costs.

Aged↗
PubMed1995

Variability in measurement of abdominal aortic aneurysms. Abdominal Aortic Aneurysm Detection and Management Veterans Administration Cooperative Study Group.

PURPOSE: The purpose of this study was to report interobserver and intraobserver variability of computed tomography (CT) measurements of abdominal aortic aneurysm (AAA) diameter and agreement between CT and ultrasonography observed in the course of a large, multicenter, randomized trial on the management of small AAAs. METHODS: CT measurements of AAA diameter from participating centers were compared with measurements made from the same scan by a central laboratory. Blinded central remeasurement of a randomly selected subset of these CT scans was used to assess intraobserver variability. Agreement between AAA measurements by CT and ultrasonography done within 30 days of each other was also assessed. RESULTS: For interobserver pairs of local and central CT measurements of AAA diameter (n = 806), the difference was 0.2 cm or less in 65% of pairs, but 17% differed by at least 0.5 cm. For intraobserver pairs of central CT remeasurements (n = 70), 90% differed by 0.2 cm or less, 70% were within 0.1 cm, and only one differed by 0.5 cm. Of 258 ultrasound-measured and central CT pairs, the difference was 0.2 cm or less in 44% and at least 0.5 cm in 33%. Ultrasound measurements were smaller than central CT measurements by an average of 0.27 cm (p < 0.0001). Local CT and ultrasound measurements showed a marked preference for recording by half centimeter. CONCLUSIONS: A high degree of precision is possible in CT measurement of AAA diameter, but this precision may not be obtained in practice because of differences in measurement techniques. Differences between imaging modalities increase variability further. Variations in AAA measurement of 0.5 cm or more are not uncommon, and this should be taken into account in management decisions. Efforts to reduce variation in measurement are warranted and might include (1) seeking agreement between surgeons and radiologists on a precise definition of AAA diameter, (2) limiting the number of radiologists who measure AAAs, and (3) use of calipers and magnifying glass for CT measurements.

Aged↗
PubMed1994

Carotid endarterectomy without arteriography: the preeminent role of the vascular laboratory.

The classic workup of patients considered for carotid endarterectomy (CE) has included contrast arteriography to delineate the nature and extent of the arterial pathology. Noninvasive testing (NIT) consisting of duplex scanning plus sound spectrum analysis is an alternative method for accurately evaluating the carotid bifurcation. The accuracy of our laboratory in comparing NIT to contrast arteriography has been established by use of the guidelines suggested by the Intersocietal Commission for the Accreditation of Vascular Laboratories. Forty-two patients underwent CE based on NIT alone. Seventeen had hemispheric transient ischemic attacks or minor strokes, six had amaurosis fugax, three had nonspecific symptoms, and 16 were asymptomatic. NIT identified a severe stenosis that was limited to the carotid bifurcation; the internal carotid artery distal to the bulb was normal. The predicted stenotic atherosclerotic lesion was confirmed at operation in all patients. One patient had a high bifurcation that required an extension of the original incision. Of three undiagnosed kinked distal internal carotid arteries found at operation, only one required surgical correction. No transient ischemic attacks, strokes, or deaths occurred postoperatively. CE can be performed in selected patients based on NIT alone, obviating the mortality, morbidity, and cost of arteriography. This algorithm demands that the NIT is unequivocal and the accuracy of the testing laboratory is established and maintained according to published standards.

Arteriosclerosis↗
PubMed1994

Design of the abdominal aortic Aneurysm Detection and Management Study. ADAM VA Cooperative Study Group.

PURPOSE: This study describes the design of an ongoing randomized trial intended to determine which of two strategies is superior for managing small abdominal aortic aneurysms (AAA). METHODS: Patients aged 50 to 79 years with AAA 4.0 to 5.4 cm in diameter as determined by computed tomography (CT) who are not at high surgical risk are randomized to either repair of the AAA, called "immediate surgery," or follow-up of the AAA with ultrasonography or CT every 6 months, reserving surgery for those aneurysms that enlarge to 5.5 cm, enlarge rapidly, or become symptomatic, called "selective surgery." RESULTS: The primary outcome measure is all-cause death, and secondary outcome measures are AAA-related death, morbidity, and general health status. The study design calls for 1350 patients to be randomized and monitored for a mean of 5 years. A second objective of the study is to accurately define the prevalence and risk factors for AAA with use of information from the large screening program established to detect AAA for recruitment into the randomized trial. CONCLUSIONS: By the end of 1993, 38,697 patients had been screened with ultrasonography, accounting for about three fourths of new randomizations, and 330 patients had been enrolled (70% of the target rate).

Aged↗
PubMed1994

Successful treatment of prolonged superior vena cava syndrome with thrombolytic therapy: a case report.

Superior vena cava (SVC) syndrome is most commonly due to direct compression of the SVC by a tumor. Recently, there has been an increase in the number of cases of SVC syndrome associated with chronic indwelling central venous catheters. We present a case history of a patient with prolonged symptoms of SVC syndrome that was successfully treated with catheter-directed (intraclot) infusion thrombolytic therapy with urokinase. The treatment, prevention, and incidence of SVC syndrome caused by thrombosis associated with catheters is discussed.

Aged↗
PubMed1994

Intraoperative duplex scanning and late carotid artery stenosis.

PURPOSE: The purpose of this study was to assess the effect of intraoperative duplex scanning on early and late results after carotid endarterectomy. METHODS: We reviewed 316 carotid arteries in 283 patients who underwent operation since 1986. The results of intraoperative ultrasonography were normal in 254 (80.4%) and abnormal in 62 (19.6%). We did not reexplore 53 (85.5%) of the abnormalities because the defect was minor, 2 to 3 mm or less. These defects were retained atheroma in the common carotid artery (n = 35), internal carotid artery (ICA) (n = 5), external carotid artery (n = 2), small frond in the bulb (n = 2), thickened wall of the vein patch (n = 2), and ICA kink (n = 7), two of which were associated with retained atheroma. Nine defects (14.5%) were reexplored and repaired; there were seven flaps, one residual plaque, and one case with turbulent flow alone. RESULTS: Patients with a normal examination result had an early ICA occlusion rate of 0.79% (n = 2), an early stroke rate of 1.6% (n = 4), and one death (0.4%). In the unrepaired group these rates were 1.9% (n = 1) and 1.9% (n = 1), respectively. No occlusion occurred in the repaired group, but one preexisting cerebrovascular accident worsened immediately after operation. Frequency analysis and B-mode imaging were performed after operation and every 6 to 12 months in all patients (mean 21.6 months). A greater than 75% area stenosis was found in nine (17%) of the 53 unrepaired carotid arteries, but in only four (4.3%) of the 254 carotid arteries lacking defects and in one of the reopened group (p < 0.001). There have been no late strokes, and only three late transient ischemic attacks overall. CONCLUSIONS: A normal intraoperative scanning result obtained after carotid endarterectomy is associated with improved late patency rates. Even small defects appear to be associated with an increased incidence of late restenosis, reemphasizing the importance of technical perfection.

Adult↗
PubMed1993

An 11-year experience with aortofemoral bypass grafting.

Over the past 11 years, 224 patients (440 limbs) underwent aortofemoral bypass grafting for claudication (63%) or limb-threatening ischemia (37%). The distal anastomosis included the profunda femoris artery directly or only as a profundaplasty in 163 limbs (37.0%). Concomitant distal bypasses were carried out in 19 limbs (4.3%). The perioperative mortality rate was 4.9%; over half of the deaths (six) were from myocardial infarction. There were ten early graft limb occlusions (2.3%). Only five major amputations (1.1%) occurred. Long-term follow-up of 416 limbs averaged 58.5 (range 2-142) months. Cumulative primary and secondary patency rates were 88 and 93% respectively at 5 years, and 73 and 89% respectively at 10 years. The cumulative limb salvage rate was 95% at 5 years and 91% at 10 years. Improvement of claudication or relief from limb-threatening ischemia occurred in 90% of limbs early after treatment. Only 5.9% of limbs were worse after operation. During follow-up, 55 patients (38.5%) died, over half from cardiac causes. Long-term graft-related complications included pseudoaneurysm in 16 limbs (3.8%) and graft limb thrombosis in 33 (7.9%), occurring at a mean of 57.8 and 24.8 months respectively. Graft infection occurred in four patients (1.9%). Excluding operations for graft infection, the operative mortality rate in 72 reoperations on 45 patients was 5.5%. In summary, aortofemoral bypass grafting can be performed safely with excellent long-term patency and limb salvage rates. Improvements in the perioperative mortality rate could best be addressed by improvements in cardiac evaluation and perioperative monitoring. Long-term graft limb complications do occur and, therefore, these patients require lifetime surveillance.

Adult↗
PubMed1991

Inflow atherosclerotic disease localized to the common femoral artery: treatment and outcome.

Severe occlusive disease of the common femoral artery without significant aortoiliac disease is not common in our experience. Since 1978 we have operated upon 29 limbs in 22 patients (mean age 60) with localized common femoral artery disease. Indications for operation were claudication in 31% and impending limb loss in 69%. Operations included common femoral artery endarterectomy with patch angioplasty (19 limbs), patch angioplasty alone (two limbs), and common femoral artery endarterectomy without a patch (three limbs). Operative mortality was zero; there were nine wound complications, one patient had a myocardial infarction with early thrombosis. Symptomatic relief was obtained in 20 of 22 patients. All minor amputations healed. The mean postoperative ankle/brachial index increased to 0.67 from 0.49. Mean follow-up is 37 months (one-118 months); there have been 10 late deaths. Cumulative two and five year patency rates are 82% and 74%, limb salvage is 80% and 80%, respectively. Major amputations were required in five patients at two, two, 12, 23, and 68 months. Further inflow procedures were required in four patients: three aortobifemoral bypasses and one axillofemoral bypass. Although this disease has an uncommon inflow level, it is amenable to safe, durable, local procedures.

Aged↗
PubMed1990

Postoperative chylous ascites: diagnosis and treatment. A series report and literature review.

The accumulation of chylous fluid in the abdominal cavity is an infrequent yet alarming complication in abdominal surgery. Excessive lymphatic leakage is occasionally encountered in the course of operations at the base of the mesentery or retroperitoneum. A source can usually be identified and the leak controlled at the time of laparotomy by suture or clip. In the region of presumed leakage the importance of these efforts is reinforced by the are patient in whom such leakage persists, creating problems in recognition and management postoperatively. The development of this complication in a patient undergoing total abdominal colectomy and left-sided hepatic lobectomy prompted a review of our experience and a literature review. We report four cases of postoperative chylous ascites seen over 5 years. The fluid accumulation followed operations on the abdominal aorta (two patients) and on the colon and liver (one patient) and after a mesocaval shunt procedure (one patient). Two patients responded to low-fat, medium-chain triglyceride diets; one patient required peritoneovenous shunting; and one patient died of progressive nutritional deterioration. We review the recognition and management of chylous ascites based on our experience and that reported elsewhere.

Aged↗
PubMed1990

An evaluation of external jugular vein patch angioplasty after carotid endarterectomy.

Seventy-six patients had 91 internal carotid endarterectomies closed with patch angioplasty. There were 36 redo and 55 primary procedures. External jugular vein was used as the patch material in 38, facial vein in nine, Dacron in seven, polytetra flour ethylene (PTFE) in nine, and saphenous vein in 28 operations. There were no perioperative deaths. Five patients required reoperation, but only one required replacement of a defective facial vein. There were five postoperative strokes, but two were related to a contralateral occlusion. Two of the three ipsilateral strokes had a temporary indwelling shunt. Only one patient returned with recurrent neurologic symptoms. Five other restenoses of greater than 75 per cent were noted in three patients. One false aneurysm occurred three months after an external jugular vein patch angioplasty. External jugular vein, although requiring careful handling, is conveniently located in the operative field, does not appear to be associated with increased complications, has excellent long-term results, and allows preservation of the saphenous vein for other bypass surgery.

Adult↗
PubMed1989

Use of sequential B-mode ultrasonography to manage abdominal aortic aneurysms.

The utility and safety of sequential B-mode ultrasonography to treat male patients with small (less than 6.0 cm in diameter) abdominal aortic aneurysms (AAAs) were studied retrospectively in 149 consecutive patients. Sixty-three of these patients have had operative repair of the AAA. Eight-six remain unoperated on. Mean growth rate was 0.79 cm/y (1.06 cm/y in the operated-on group and 0.36 cm/y in the unoperated-on group). Seven patients sustained rupture of the AAA during follow-up and 4 patients died as a consequence of elective repair, for a combined mortality rate of 7.4% (11/149). Only one AAA that was less than 5.0 cm ruptured. This has proved to be an effective way to manage AAAs in this population.

Aged↗
PubMed1989

Mechanical factors predisposing to intimal hyperplasia and medial thickening in autogenous vein grafts.

Autogenous veins undergo intimal hyperplasia and medial thickening when used as arterial bypass grafts. Exposing veins to arterial pressure and flow subjects them to three static deformations, three static stresses, increased pulsatile deformations, pulsatile stresses, and altered shear stress at the blood-intima interface. All of these occur simultaneously; thus it is unclear which of these nine mechanical factors predispose to the histologic changes that occur in the vein wall. Three sequential experiments were performed in 38 dogs to determine the role of each of these factors. Results showed that intimal hyperplasia is best associated with low flow velocity, a factor correlated with low blood-artery shear stress. By contrast, medial thickening is best associated with increased deformation of the vein wall in the circumferential direction (increased diameter). These findings correlate with clinical responses of vein grafts.

Anastomosis, Surgical↗
PubMed1988

Mechanical and histologic changes in canine vein grafts.

Mechanical and histological studies were performed on dog femoral veins after their implantation as grafts to bypass the ligated femoral arteries. The vein grafts dilated rapidly after implantation with 90% of maximum dilation occurring at 4 weeks. Both the native veins and the vein grafts were highly compliant up to 35-50 mm Hg, but were virtually nondistensible at higher pressures. When implanted with end-to-side anastomoses (end of vein to side of artery), the compliance of the anastomotic region resembled that of the artery rather than that of the vein. This was due to the distensibility of the artery at arterial pressure, as compared with the almost rigid vein. Histologic examination showed that intimal hyperplasia was greater after end-to-side anastomosis than after end-to-end anastomosis (P less than 0.05) and that this increased hyperplasia was reduced by treatment with aspirin and dipyridamole (P less than 0.05). By contrast, medial thickening was increased in all grafts compared with native veins (P less than 0.05), but was not different in end-to-end, end-to-side, and aspirin/dipyridamole-treated end-to-side grafts. These data suggest that intimal hyperplasia and medial thickening are separate responses to different stimuli.

Anastomosis, Surgical↗
PubMed1988

Secondary vascular procedures with polytetrafluoroethylene grafts for lower extremity ischemia in a male veteran population.

Secondary vascular procedures to below-knee vessels for lower extremity ischemia present a challenge to the vascular surgeon. Autogenous vein is often unavailable and failure of the previous bypass often limits the choice of distal vessels suitable for revascularization. This dilemma raises the question of amputation vs secondary vascular surgery. To address this question we reviewed the results of our previous aggressive approach to revascularization in a select group of 25 patients (26 limbs) who had secondary procedures with polytetrafluoroethylene grafts to tibial vessels or the infragenicular popliteal artery with single-vessel runoff. Nine of these 26 bypasses (35%) have remained patent for a mean of 17.2 months and no amputations have been done in this group. The other 17 bypasses (65%) have occluded from 1 day to 36 months postoperatively (mean 4.3 months); 15 of these limbs have required major amputation (58%). Ten were performed within the first 3 months postoperatively. Thirteen of the 25 patients died in the follow-up period (mean 27.5 months); five of these patients had viable limbs. Of 12 surviving patients (mean follow-up 19.9 months), six had viable limbs and six have required amputation. These results indicate that patients having secondary vascular surgical procedures with polytetrafluoroethylene grafts to tibial vessels have a high amputation rate and poor overall survival. Within this select group of patients, those who could walk with the aid of a prosthesis should be considered as candidates for primary amputation. This would facilitate rehabilitation and avoid the anguish of recurrent graft failure and multiple procedures.

Adult↗
PubMed1988

Anomalous branches of the cervical internal carotid artery: two cases of clinical importance.

Anomalous branches of the cervical portion of the internal carotid artery are rare. Reports in which these anomalous branches are of any clinical importance are even more rare. We are reporting two cases in which the anomalous branch maintained patency of the cervical portion of the proximally occluded internal carotid artery. Both patients initially had hemispheric symptoms appropriate to the affected internal carotid artery. This article details angiographic methods to demonstrate the unusual anatomic and pathologic aspects of these cases and the successful operative approach.

Aged↗
PubMed1987

Reproducibility of transcutaneous continuous-wave Doppler testing of the carotid arteries.

Hand-held, continuous-wave Doppler probes, coupled with sound spectral analysis, can successfully predict carotid artery stenosis. Changing either the emitting frequency of the probe, the beam/artery angle of the carotid flow velocity (e.g. cardiac output) may alter the recorded frequency shifts. These effects raise questions as to the efficacy of this technique to serially follow carotid atheroma for progressive stenosis. To test the inherent problems with this methodology, a study of reproducibility was conducted. Two Doppler probes (5 MHz and 8 MHz) were compared at the same sitting in 24 patients; 12 were restudied on two subsequent occasions. Peak systolic frequency was 135% higher with the 8 MHz probe; this was lower than the 160% calculated by substitution for emitting frequency in the Doppler formula. The linear correlation coefficient of the two probes was 0.88. In relationship to established laboratory criteria of a greater than 75% area stenosis, no errors were noted with the 5 MHz probe while four errors were noted with the 8 MHz probe. A serial study variation of peak systolic frequency was noted for both probes; these variations did not cross established criteria levels of a severe stenosis when the 5 MHz probe was used, but did with the 8 MHz probe for two carotids. A standard examining probe is recommended. Angle and cardiac output changes do result in peak systolic frequency variation from test to test, but these were not clinically significant with the 5 MHz probe. Thus, significant changes during follow-up testing should provide an index of evolving carotid stenosis.

Arterial Occlusive Diseases↗
PubMed1987

Effect of prior arterial reconstruction on the outcome of femorofemoral bypass.

To study the effect of previous arterial reconstruction at the femoral level on the outcome of femorofemoral bypass, 63 male patients who were operated upon from 1977 to 1985 were reviewed retrospectively. Thirty-four patients had no previous surgery (Group A) and 29 had had previous femoral-level surgery (Group B). Both groups were comparable for risk factors and indications for operation. Previous reconstructions included 36 inflow and 24 outflow procedures. Operatively, recipient profundaplasty was required in 79 per cent of Group B versus 32 per cent in Group A. Early results (fewer than 30 days) were comparable for mortality, graft thrombosis, and amputation. Late results showed similar graft thrombosis and cumulative patency rates. The need for reoperation (32 vs 9%) and major amputation (14.8 vs 3%) were increased in Group B but not significantly different. Primary and secondary femorofemoral bypass are both efficacious with the outcome determined by the progression of distal atherosclerosis.

Arteriosclerosis↗