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Biomedical subjects

G L'Italien

Publications and source records attributed to G L'Italien.

15 recordsLinked to original sources
PubMed2001

A health perception score predicts cardiac events in patients with heart failure: results from the IMPRESS trial.

BACKGROUND: New York Heart Association (NYHA) class and treadmill exercise test variables are widely used for estimating prognosis and measuring the outcomes of treatment in patients with heart failure, but they do not take patients' perceptions into account. METHODS AND RESULTS: Five hundred forty-five patients enrolled in a multicenter 24-week comparison of the effects of omapatrilat and lisinopril on functional capacity in patients with heart failure reported a visual analog scale (VAS) score of their overall health perception at week 12 of the study. A total of 27 first events, defined as death or worsening heart failure (hospitalization, emergency room visit, or study discontinuation), occurred in the subsequent 12 weeks. The mean (+/-SD) health perception scores were 0.43 +/- 0.31 and 0.68 +/- 0.20 in patients with and without events, respectively (P =.0006). The risk ratio (RR) for an event associated with a decile change in the health perception score was 0.74 (95% confidence interval [CI], 0.61-0.88; P =.001). The RR was unaltered by adjustment for demographic variables, treadmill time, and NYHA functional class. Although the week 12 NYHA functional class was predictive of events (RR = 2.1; 95% CI, 1.2-4.6; P =.04), treadmill time was not (RR = 0.87; 95% CI, 0.73-1.03; P = 0.11). CONCLUSIONS: A patient-reported measure of perceived health predicts events in patients with heart failure.

Aged↗
PubMed2000

The cardiovascular event reduction tool (CERT)--a simplified cardiac risk prediction model developed from the West of Scotland Coronary Prevention Study (WOSCOPS).

The clinical decision to treat hypercholesterolemia is premised on an awareness of patient risk, and cardiac risk prediction models offer a practical means of determining such risk. However, these models are based on observational cohorts where estimates of the treatment benefit are largely inferred. The West of Scotland Coronary Prevention Study (WOSCOPS) provides an opportunity to develop a risk-benefit prediction model from the actual observed primary event reduction seen in the trial. Five-year Cox model risk estimates were derived from all WOSCOPS subjects (n = 6,595 men, aged 45 to 64 years old at baseline) using factors previously shown to be predictive of definite fatal coronary heart disease or nonfatal myocardial infarction. Model risk factors included age, diastolic blood pressure, total cholesterol/ high-density lipoprotein ratio (TC/HDL), current smoking, diabetes, family history of fatal coronary heart disease, nitrate use or angina, and treatment (placebo/ 40-mg pravastatin). All risk factors were expressed as categorical variables to facilitate risk assessment. Risk estimates were incorporated into a simple, hand-held slide rule or risk tool. Risk estimates were identified for 5-year age bands (45 to 65 years), 4 categories of TC/HDL ratio (<5.5, 5.5 to <6.5, 6.5 to <7.5, > or = 7.5), 2 levels of diastolic blood pressure (<90, > or = 90 mm Hg), from 0 to 3 additional risk factors (current smoking, diabetes, family history of premature fatal coronary heart disease, nitrate use or angina), and pravastatin treatment. Five-year risk estimates ranged from 2% in very low-risk subjects to 61% in the very high-risk subjects. Risk reduction due to pravastatin treatment averaged 31%. Thus, the Cardiovascular Event Reduction Tool (CERT) is a risk prediction model derived from the WOSCOPS trial. Its use will help physicians identify patients who will benefit from cholesterol reduction.

Age Factors↗
PubMed1997

Clinical experience with epidural cooling for spinal cord protection during thoracic and thoracoabdominal aneurysm repair.

PURPOSE: This report summarizes our experience with epidural cooling (EC) to achieve regional spinal cord hypothermia and thereby decrease the risk of spinal cord ischemic injury during the course of descending thoracic aneurysm (TA) and thoracoabdominal aneurysm (TAA) repair. METHODS: During the interval July 1993 to Dec. 1995, 70 patients underwent TA (n = 9, 13%) or TAA (n = 61) (type I, 24 [34%], type II, 11 [15%], type III, 26 [37%]) repair using the EC technique. The latter was accomplished by continuous infusion of normal saline (4 degrees C) into a T11-12 epidural catheter; an intrathecal catheter was placed at the L3-4 level for monitoring of cerebrospinal fluid temperature (CSFT) and pressure (CSFP). All operations (one exception, atriofemoral bypass) were performed with the clamp-and-sew technique, and 50% of patients had preservation of intercostal vessels at proximal or distal anastomoses (30%) or by separate inclusion button (20%). Neurologic outcome was compared with a published predictive model for the incidence of neurologic deficits after TAA repair and with a matched (Type IV excluded) consecutive, control group (n = 55) who underwent TAA repair in the period 1990 to 1993 before use of EC. RESULTS: EC was successful in all patients, with a 1442 +/- 718 ml mean (range, 200 to 3500 ml) volume of infusate; CSFT was reduced to a mean of 24 degrees +/- 3 degrees C during aortic cross-clamping with maintenance of core temperature of 34 degrees +/- 0.8 +/- C. Mean CSFP increased from baseline values of 13 +/- 8 mm Hg to 31 +/- 6 mm Hg during cross-clamp. Seven patients (10%) died within 60 days of surgery, but all survived long enough for evaluation of neurologic deficits. The EC group and control group were well-matched with respect to mean age, incidence of acute presentations/aortic dissection/aneurysm rupture, TAA type distribution, and aortic cross-clamp times. Two lower extremity neurologic deficits (2.9%) were observed in the EC patients and 13 (23%) in the control group (p < 0.0001). Observed and predicted deficits in the EC patients were 2.9% and 20.0% (p = 0.001), and for the control group 23% and 17.8% (p = 0.48). In considering EC and control patients (n = 115), variables associated with postoperative neurologic deficit were prolonged (> 60 min) visceral aortic cross-clamp time (relative risk, 4.4; 95% CI, 1.2 to 16.5; p = 0.02) and lack of epidural cooling (relative risk, 9.8; 95% CI, 2 to 48; p = 0.005). CONCLUSION: EC is a safe and effective technique to increase the ischemic tolerance of the spinal cord during TA or TAA repair. When used in conjunction with a clamp-and-sew technique and a strategy of selective intercostal reanastomosis, EC has significantly reduced the incidence of neurologic deficits after TAA repair.

Adult↗
PubMed1997

Thoracoabdominal aneurysm repair: perspectives over a decade with the clamp-and-sew technique.

OBJECTIVES: Experience over a decade with thoracoabdominal aortic aneurysm (TAA) repair using a clamp-sew technique was reviewed to compare overall results with alternative operative methods. SUMMARY BACKGROUND DATA: Controversy continues as to the optimal technique for TAA repair, with frequent contemporary emphasis on bypass-distal perfusion methods. Proponents of this technique claim improved results compared to those of historic control subjects in the parameters of operative mortality, postoperative renal failure, and lower extremity neurologic deficit. METHODS: Over the interval from 1987 to 1996, 160 TAA repairs (type I, 32%; type II, 15%; type III, 34%; and type IV, 19%) were performed in 157 patients with a mean age of 70 years and a male-to-female ratio of 1/1. Clinical features included ruptured TAA (10%), urgent operation (22.5%), and aortic dissection (18%). Operative management used a clamp-sew technique with regional hypothermia for spinal cord (epidural cooling, since 1993) and renal protection. Variables associated with the endpoints of operative mortality or major morbidity, particularly spinal cord injury, were assessed with Fisher exact test and logistic regression; late survival was estimated with the Kaplan-Meier method. RESULTS: In-hospital mortality was 9% and was associated with operation for rupture (p < 0.005) or other acute presentation (p < 0.001). After multivariate analysis, the postoperative complication renal failure (relative risk, 6.5 [95% confidence interval, 1.8-23.6, p = 0.004]) and significant spinal cord injury (relative risk, 16.5 [95% confidence interval, 3.2-83.2, p = 0.001]) were associated independently with operative mortality. Paraparesis-paraplegia occurred in 7%, an incidence significantly (p < 0.001) less than that (18.7%) predicted for this cohort from published models. Variables associated (univariate analysis) with this complication included TAA rupture (p < 0.0001), other acute presentation or dissection (p < 0.001), prolonged (>6 hours) operation (p < 0.04), and excessive (>3 L) transfusions (p < 0.02). Operation for acute presentation or dissection (relative risk, 7.9 [95% confidence interval, 1.7-37.7, p = 0.009]) and prolonged surgery [relative risk, 7.5 [95% confidence interval, 1.5-35.3, p = 0.01]) retained independent association with paraplegia-paraparesis after multivariate analysis. Dialysis was needed in 2.5%. Late survival at 1 and 5 years was 86 +/- 2.9% and 62 +/- 5.8%, respectively. CONCLUSIONS: These data compare favorably with those from contemporary reports using other operative strategies and do not support routine adoption of bypass-distal perfusion as the preferred technique for TAA repair.

Acute Kidney Injury↗
PubMed1996

Coagulation changes during thoracoabdominal aneurysm repair.

PURPOSE: The cause of coagulopathic hemorrhage during thoracoabdominal aneurysm (TAA) repair has not been well defined in human studies. We investigated changes in the coagulation system associated with supraceliac versus infrarenal cross-clamping to address this critical issue. METHODS: Blood levels of fibrinogen, the prothrombin fragment F1.2, D-dimer, and factors II, V, VII, VIII, IX, X, XI, and XII were analyzed in 19 patients with TAAs and four patients with abdominal aortic aneurysms (AAAs) at: (A) induction; (B) 30 minutes into supraceliac (TAA) or infrarenal (AAA) clamping; (C) 30 minutes after release of supraceliac or infrarenal clamps; and (D) immediately after surgery. Preoperative and intraoperative variables, including but not limited to aneurysm type, pathologic findings, comorbid conditions, clamp times, volume and timing of blood products, and clinical outcome, were prospectively recorded. Significance was determined by analysis of variance, Student's t test, and univariate linear regression. RESULTS: Levels of fibrinogen and factors II, V, VIII, VIII, IX, X, XI, and XII decreased (p < 0.05) at time B versus time A and returned to near baseline by time D. D-dimer and F1.2 increased starting at time B and reached significance (p < 0.05) by time D. Data points were compared for the TAA and AAA groups. Although AAA groups demonstrated a trend to factor activity reduction and increased fibrinolysis, the effect was much less pronounced than in TAA and did not approach significance. No correlation of coagulation change with clamping time was present; however, visceral clamping times were all less than 65 minutes (mean, 44 minutes). Blood and factor replacement was initiated after time B. Univariate regression analysis of factor level versus total blood replacement demonstrated a significant (p < 0.04) correlation between the reduction in the levels of factors II, V, VII, VIII, X, and XII, and the increase in the level of D-dimer at time B and subsequent total blood replacement. CONCLUSIONS: Thoracoabdominal aneurysm repair is associated with a reduction in clotting factor activity and an increase in fibrinolytic function, which occurs after placement of the supraceliac clamp. Explanations include visceral ischemia or a greater and longer ischemic tissue burden as the likely cause of coagulation alterations. Total blood replacement during TAA procedures was correlated to the degree of factor reduction and fibrinolysis at the time of visceral cross-clamping. An aggressive approach to early blood component replacement and to coagulation monitoring could lessen blood loss during TAA repair and avoid potentially disastrous bleeding complications.

Aortic Aneurysm, Abdominal↗
PubMed1995

Simultaneous aortic and renal artery reconstruction: evolution of an eighteen-year experience.

PURPOSE: We reviewed an 18-year experience with combined abdominal aortic and renal artery reconstruction (AOR) with a particular focus on patients' clinical risk profile and surgical results in contemporary practice as compared with earlier experience. METHODS: One hundred seventy patients underwent AOR during the interval January 1, 1976 to June 30, 1994. To examine parameters representative of current practice, the cohort was divided into group I patients (n = 110) treated before 1990 and group II (n = 60) treated between 1990 and 1994. Median follow-up duration for the entire cohort was 8.4 +/- 0.6 years. Renal artery reconstruction patency and patient survival rates were calculated by life-table methods. Logistic and Cox regression analysis were used to determine predictors of perioperative and long-term morbidity/mortality rates. RESULTS: Although demographic features changed little over the review period, the detection (56% vs 73%, p = 0.03) and treatment with percutaneous transluminal coronary angioplasty/coronary artery bypass grafting (11% vs 40%, p = 0.0001) of associated coronary artery disease were more frequent in group I patients. The operative mortality rate for the entire cohort was 6.5% (group I = 9% vs group II = 2%, p = 0.06). Changing trends of surgical techniques over the review period included (group I vs II, respectively) increased use of bilateral simultaneous renal artery repair (12% vs 25%, p < 0.005) and transaortic endarterectomy as the renal artery reconstruction technique (3% vs 25%, p < 0.0001). Favorable response in blood pressure control was noted in 68% of group II patients. The cumulative 5-year survival rate for all patients was 75% with an initial serum creatinine of 2.0 mg/dl or greater being the only negative predictor of late survival after regression analysis. CONCLUSION: The current operative mortality rate for AOR is in the range anticipated for aortic surgery alone, and this appears to be related to improved detection and treatment of associated coronary artery disease and intervention before major deterioration in renal function. These findings coupled with currently available natural history data relative to renovascular disease justify an aggressive approach with AOR when significant renal artery stenosis is detected during evaluation of aortic disease.

Aged↗
PubMed1993

Claudication in the setting of plethysmographic criteria for resting ischemia: is surgery justified?

Objective noninvasive criteria for resting ischemia are sometimes found in patients with milder clinical complaints. If noninvasive information can predict irrevocable progression to resting ischemia, instances of tissue loss theoretically could be prevented by early intervention. Accordingly, we investigated the clinical outcome in 51 claudicators with pulse volume recorder and/or ankle-brachial index (ABI) criteria for ischemia at rest. Patients with type IV (markedly blunted) or type V (flat) ankle or transmetatarsal pulse volume recordings and/or ABI < 0.5 and accompanying claudication were identified. Resting ischemia and/or tissue necrosis developed in 29% of patients and necessitated vascular reconstruction within 36 months. One patient had a primary above-knee amputation at a different institution and 14 patients underwent successful revascularization. In 3 of 14 patients, reconstruction was accompanied by digit or transmetatarsal amputation. No limbs were lost in the revascularized group. Noninvasive criteria for resting ischemia in patients with claudication alone portend a high rate of progression to resting ischemic symptoms. At present the use of clinical criteria and careful follow-up would permit a high rate of foot and limb salvage in those whose ischemia progresses and would prevent unnecessary surgery in the remaining patients. Further prospective definition of patients at risk for progression of ischemia might help prevent tissue loss in selected patients.

Aged↗
PubMed1993

The potential for lower extremity revascularization without contrast arteriography: experience with magnetic resonance angiography.

PURPOSE: We report an initial experience with 24 patients studied between March 1990 and April 1992 with magnetic resonance angiography (MRA) for lower extremity occlusive disease. METHODS: All patients underwent vascular intervention with either balloon angioplasty or bypass grafting, and in six patients this intervention was based on MRA findings alone. Eighteen patients were studied with both MRA and contrast arteriography, and there was observed agreement between the two studies in 98% of all arterial segments examined. RESULTS: Agreement between MRA and contrast arteriography was uniform for arterial segments below the inguinal ligament. Intraoperative findings and favorable early results of seven bypass grafts performed in six patients after MRA alone suggested this was a valid approach for patients at prohibitive risk of complications from contrast arteriography. CONCLUSIONS: Magnetic resonance angiography is accurate in demonstrating relevant anatomy in peripheral arterial occlusive disease and in selected patients may eliminate the need for contrast arteriography before lower extremity revascularization.

Angiography↗
PubMed1993

Ambient oxygen tension modulates endothelial fibrinolysis.

PURPOSE: Vascular procedures reoxygenate ischemic endothelial cells (EC) and arterialize saphenous vein (HSV) EC. The balance between the EC-derived fibrinolytic components, plasminogen activator (tPA), and plasminogen inhibitor (PAI-1) contributes to maintaining thromboresistance. This balance also affects proteolysis through plasmin generation, mediating matrix metabolism endothelial migration, angiogenesis, and theoretically affecting the development of intimal hyperplasia. METHODS: To explore the impact of varying oxygen tensions on EC fibrinolysis, HSV and human umbilical vein (HUV) were subjected to Po2 of 40 mm Hg for 24 hours with restoration of Po2 to 150 mm Hg for 24 hours. The tPA and PAI-1 antigen and tPA/PAI-1 antigen ratio in conditioned media (CM), expressed as increases or decreases % change, normalized for cell count, versus controls, were analyzed by enzyme-linked immunosorbent assay. Cellular tPA and PAI-1 mRNAs were assessed by Northern analysis. RESULTS: The tPA but not PAI-1 was significantly decreased after the first 24 hours in HSVEC and significantly decreased after 48 hours in both HUVEC and HSVEC when compared with controls. Messenger RNA for tPA was unchanged but PAI-1 mRNA increased significantly for HSVEC and HUVEC after 24 hours of Po2 of 40 mm Hg, returning to baseline within 24 hours of Po2 to 150 mm Hg restoration. CONCLUSIONS: These data support the hypothesis of a fibrinolytic shift after altered ambient O2 tensions exposure in endothelium and demonstrate that HSVEC are more sensitive to altered O2 tension than HUVEC. Altered O2 tensions depress EC fibrinolysis in this model.

Atmospheric Pressure↗
PubMed1987

Effect of compliance mismatch on vascular graft patency.

The hypothesis that a mismatch in compliance between a vascular graft and its host artery is detrimental to graft patency was tested by implanting paired arterial autografts, prepared with differential glutaraldehyde fixation of carotid arteries in the femoral arteries of dogs. These grafts differed only in circumferential compliance: they were 100% (compliant) vs. 40% (stiff) as compliant as the host artery. Their flow surfaces were equivalent, as determined by physicochemical measurements and scanning electron microscopy; both lacked viable cells, as determined by in vitro cell culture. In 14 dogs, eight stiff and two compliant grafts became occluded within 3 months, the latter doing so within 24 hours after their contralateral counterparts. Cumulative patencies were 85% and 37% for compliant and stiff grafts, respectively (p less than 0.05) and 100% and 43%, excluding the two dogs with bilateral graft failures (p less than 0.01). We conclude that even with near optimal flow surfaces, compliance mismatch is deleterious to graft patency.

Animals↗
PubMed1983

Noninvasive intraoperative assessment of arterial reconstruction. Experimental validation of the role of central and regional hemodynamics.

We developed an experimental model of graded arterial stenosis to emulate conditions that might be encountered immediately following arterial grafting. Noninvasive measurements of systolic BP and limb blood flow were recorded with a Doppler probe and segmental air plethysmography, respectively, under conditions of different cardiac output and local arterial resistance. These measurements were correlated with direct intra-arterial pressure recordings and flow measurements taken with an electromagnetic flowmeter. There was an excellent correlation between noninvasive and intra-arterial measurements of systolic pressure over a range of cardiac outputs and degree of arterial stenosis. Pulse volume recordings correlated with direct measurements of blood flow at high and baseline cardiac outputs, but the calibration of pulse volume amplitude varied between cuff applications in this canine model. Noninvasive intraoperative monitoring techniques can faithfully represent known physiologic responses to graded arterial stenoses, irrespective of a high cardiac output or peripheral vasodilation.

Animals↗
PubMed1983

The effect of halothane anesthesia on platelet aggregation in vivo: decreased deposition on polytetrafluoroethylene arterial grafts in dogs.

The technique of gamma-imaging can be used to study the deposition of 111In-labeled platelets onto synthetic arterial grafts in vivo. Recent results suggested that platelet uptake on polytetrafluoroethylene (PTFE) grafts might depend on the choice of anesthetic. To evaluate the effect of anesthesia a series of experiments was performed in seven dogs wherein each animal served as its own control. The first of paired femoral or carotid PTFE grafts was inserted with the animal under pentobarbital anesthesia, and the graft was imaged for 90 minutes. A second graft was then inserted after at least 1 hour of halothane anesthesia. The mean activity ratio (describing platelet deposition) in the grafts inserted when only pentobarbital anesthesia was used was 7.04 +/- 0.55, compared to 1.20 +/- 0.07 in the grafts inserted with halothane anesthesia (P less than 0.01). Halothane anesthesia led to significantly decreased platelet uptake on canine PTFE arterial grafts. This effect was reversible, though not immediately, with no significant difference in graft activity noted by the day following surgery.

Anesthesia, Inhalation↗
PubMed1981

Anatomic localization of atherosclerotic lesions by hemodynamic tests.

Use of noninvasive tests to assess the severity of lower-extremity occlusive lesions is generally accepted. To evaluate the effectiveness of noninvasive vascular-laboratory tests in locating atherosclerotic lesions, the results of hemodynamic studies in 100 patients were reviewed by both skilled observers and a vascular computer, and compared with angiograms. The results of the comparison suggest a remarkable sensitivity of the vascular-laboratory tests in locating significant arterial obstructions, and underscore that the great predictive value of a negative results gives the physician reliable information on the patency of a given arterial segment. Computer interpretation proved less accurate than that of the vascular-laboratory personnel.

Adult↗
PubMed1980

Complementary methods for evaluating carotid stenosis: a biophysical basis for ocular pulse wave delays.

Attempts to noninvasively estimate the significance of carotid arterial stenoses have resulted in a recent technological explosion. Ocular pulse wave timing [oculoplethysmography (OPG) pulse delay] has been strongly promulgated but also criticized on theoretical grounds and for lack of physiologic validation. Audiofrequency analysis of carotid bruits (carotid phonoangiography CPA) has been combined with OPG allegedly to improve accuracy. To evaluate these methods in a controlled model, we studied the effects of graded unilateral stenoses in the canine carotid artery on physiological parameters and associated OPG and CPA recordings. Arterial compliance was calculated from simultaneous diameter and pressure recordings distal to the stenosis. OPG time delay correlated directly with reductions in flow and pressure and with increasing arterial compliance (P less than 0.01). Thus, the delay is caused at least partially by a decreased pulse wave velocity, resulting from the increased compliance distal to stenoses associated with a significant pressure gradient. OPG is most discriminating for stenoses of higher grades. Because bruits arise from flow disturbances that occur even with moderate degrees of stenosis, CPA provides diagnostic information before profound flow reduction occurs. This study illustrates the value of complementary methods for analyzing complex hemodynamic phenomena and provides evidence to support use of the pulse delay concept to diagnose arterial disease.

Angiography↗