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Biomedical subjects

Anthony J Comerota

Publications and source records attributed to Anthony J Comerota.

29 records · Page 2Linked to original sources
PubMed2003

Tissue (muscle) oxygen saturation (StO2): a new measure of symptomatic lower-extremity arterial disease.

OBJECTIVES: Near-infrared spectroscopy provides a noninvasive method of measuring tissue oxygen saturation and has been used to monitor extremity compartment syndrome. Tissue O(2) saturation (StO(2)) is potentially useful in assessing patients with peripheral arterial disease (PAD). The purposes of this feasibility study are to (1) explore the diagnostic sensitivity of StO(2) in subjects with PAD and symptoms of intermittent claudication (IC) compared with normal subjects, and (2) correlate the change in StO(2) during and after exercise with the ankle brachial index (ABI) in patients with IC. Material and methods Forty-nine subjects, 35 normal and 14 PAD, from two centers were evaluated in a prospective cross-sectional analysis comparing StO(2) by using the InSpectra tissue spectrometer and ABI at rest (baseline) and after treadmill exercise. Measurements were obtained at baseline and peak exercise (normal subjects) and at baseline, initial claudication distance (ICD) and absolute claudication distance (ACD) in PAD subjects. Endpoint values were the mean of 15 data points. Times to 50% of StO(2) recovery to baseline (T(50)) and complete recovery to baseline (T(100)) were measured. Receiver-operator characteristic curves were constructed to assess the sensitivity/specificity values associated with various StO(2) cut-points. RESULTS: The PAD patients were older (P =.0002) and 57% were male, compared with 37% males in the normal group. The ABI was 0.68 +/- 0.14 in PAD patients versus 1.14 +/- 0.08 in normal subjects (P <.0001). The baseline StO(2) was 65% in both groups. The peak exercise StO(2) was significantly lower and the absolute change in StO(2) and the percent change in StO(2) were significantly greater in PAD patients (P < 0.45). The T(50) and T(100) were longer in the PAD patients compared to normal subjects (P =.0001 and.002, respectively). A T(50) of >70 seconds yielded a sensitivity of 89% and a specificity of 85% for PAD. CONCLUSIONS: StO(2) is a new and potentially useful technique to evaluate patients with PAD. Resting StO(2) was similar in PAD-IC subjects and normals. There was a significantly greater drop in StO(2) and longer recovery times in PAD-IC subjects. Interestingly, StO(2) at the ICD and ACD was similar. StO(2) offers a different and perhaps more appropriate end point for diagnosis and monitoring of the management of patients with PAD, and may offer additional insight into the pathophysiology of exercise-induced muscle ischemia and its recovery.

Adult↗
PubMed2003

The case for early detection and integrated intervention in patients with peripheral arterial disease and intermittent claudication.

Peripheral arterial disease (PAD) is defined as atherosclerotic disease of the aorta and arteries of the lower extremities. The most frequent manifestations of ischemia occur in the lower extremity arteries, with intermittent claudication as the most common symptom. Intermittent claudication, which is characterized by temporary pain brought on by muscle exertion, is usually experienced in the calf muscles and typically subsides with rest. The atherosclerotic nature of PAD/intermittent claudication makes it an important predictor of risk for cardio- and cerebrovascular disease, as well as limb loss. Thus, active screening and early diagnosis of PAD/intermittent claudication, in addition to aggressive management that incorporates risk factor modification, exercise therapy, platelet inhibition and other appropriate pharmacotherapy, and potential lifestyle changes, play important roles in overall patient management. Pharmacotherapy with cilostazol has been shown to improve maximal and pain-free walking distances. Uncontrolled and severely debilitating intermittent claudication may require revascularization.

Arterial Occlusive Diseases↗
PubMed2002

Naked plasmid DNA encoding fibroblast growth factor type 1 for the treatment of end-stage unreconstructible lower extremity ischemia: preliminary results of a phase I trial.

OBJECTIVE: The objective of this study was to evaluate the safety and tolerance of increasing single and repeated (n = 2) doses of intramuscular naked plasmid DNA encoding for fibroblast growth factor (FGF) type 1 (NV1FGF) administered to patients with unreconstructible end-stage peripheral arterial occlusive disease (PAD). The secondary objectives were to determine the biologic activity of NV1FGF on hemodynamic and clinical parameters associated with improved perfusion. METHODS: Fifty-one patients with unreconstructible peripheral arterial occlusive disease with rest pain or tissue necrosis underwent treatment with intramuscular NV1FGF. Increasing single (500, 1000, 2000, 4000, 8000, and 16,000 microg) and repeated (2 x 500, 2 x 1000, 2 x 2000, 2 x 4000, and 2 x 8000 microg) doses of NV1FGF were injected into the ischemic thigh and calf. Arteriography was performed before treatment and was repeated 12 weeks after treatment. Side effects and serious adverse events were monitored. Measurements of plasma and urine levels were performed to evaluate NV1FGF plasmid distribution. Serum FGF-1 was measured as an analysis of gene expression at the protein level. Transcutaneous oxygen pressure, ankle brachial index, toe brachial index, pain assessment with visual analog scale, and ulcer healing also were assessed. The safety results are presented for 51 patients, and the clinical outcomes are presented for the first 15 patients (500 to 4000 microg) who completed the 6-month follow-up study. RESULTS: NV1FGF was well tolerated. Sixty-six serious adverse events were reported; however, none were considered to be related to NV1FGF. Four patients had adverse events that were possibly or probably related to the study treatment: injection site pain, pain, peripheral edema, myasthenia, and paresthesia. No laboratory adverse events were related to the study treatment. Two deaths remote from the treatment were considered not related. Biodistribution of plasmid was limited and transient in plasma and absent in urine. No increase in the FGF-1 serum level was detected. A significant reduction in pain (P <.001) and aggregate ulcer size (P <.01) was associated with an increased transcutaneous oxygen pressure (P <.01) as compared with baseline pretreatment values. A significant increase in ankle brachial index (P <.01) was seen. CONCLUSION: NV1FGF is well tolerated and potentially could be effective for the treatment of patients with end-stage limb ischemia. Biologic parameters indicate improved perfusion after NV1FGF administration. Dose response is not yet evident. The safety of NV1FGF and the magnitude of improvement observed in this study encourage further investigation with a placebo-controlled, double-blind clinical trial.

Adult↗
PubMed2002

Quality-of-life improvement using thrombolytic therapy for iliofemoral deep venous thrombosis.

Patients with iliofemoral deep venous thrombosis suffer the most severe postthrombotic morbidity. Techniques that effectively remove thrombus from the venous system eliminate venous obstruction and potentially preserve valvular function. This will likely reduce or avoid the postthrombotic syndrome and improve long-term quality of life. To evaluate whether catheter-directed thrombolysis is associated with improved quality of life compared with anticoagulation alone and whether outcome in the thrombolysis group is related to lytic success, 98 patients with iliofemoral deep venous thrombosis who were treated at least 6 months earlier were identified and queried with a validated health-related quality-of-life questionnaire. Sixty-eight patients were identified through the Venous Registry (a national, multicenter venous registry) and were treated with catheter-directed thrombolysis with urokinase, and 30 patients were identified by means of medical record review and were treated with anticoagulation alone. All patients were candidates for thrombolysis; however, the treatment decision was made according to physician preference. The two treatment groups did not differ significantly in average time between the reference hospitalization and first contact. No difference was found in physical functioning and well-being between the groups before the development of deep venous thrombosis. Following treatment, patients receiving catheter-directed thrombolysis reported better overall physical functioning, less stigma, less health distress, and fewer postthrombotic symptoms compared to those patients treated with anticoagulation alone. Within the thrombolysis group, successful lysis correlated with health-related quality of life. Catheter-directed thrombolysis for the management of patients with iliofemoral deep venous thrombosis significantly improves health-related quality of life compared to similar patients treated with anticoagulation alone. Improved quality of life is related to successful thrombolysis. These data offer a compelling argument for a prospective randomized study.

Adult↗
PubMedDate not supplied

Catheter-directed thrombolysis for deep venous thrombosis.

Venous thromboembolism (VTE) represents a significant clinical problem, affecting patients of all age groups, nationalities, and socioeconomic strata. Despite its prevalence, the paradigms for care are largely centered around primary or secondary prophylaxis, with less emphasis on actual treatment of the thrombus. With the recent rapid development of advanced endovascular techniques, it is now feasible to dissolve many thrombi using catheter-directed thrombolysis (CDT), and favorable clinical experience has been reported in over 600 patients. If performed safely, the purported benefits of CDT for DVT include a decreased incidence of persistent phlebitic symptoms, improved quality of life and, possibly, a decreased incidence of recurrent thrombotic events.

Anticoagulants↗
PubMedDate not supplied

Percutaneous venous valve bioprosthesis: initial observations.

Chronic deep venous insufficiency remains a major health problem in the United States and worldwide. Selected patients benefit from direct deep vein valve repair or valve transplantation; however, most are not candidates for these procedures. Experience with the bovine monocusp venous valve surgically inserted into the common femoral vein (CFV) demonstrates potential benefit and good long-term patency. A venous valve placed distal to the CFV via percutaneous access has great appeal and potential for further improving venous hemodynamics, as well as reducing ambulatory venous hypertension and ulceration. Two patients were treated with a percutaneous venous valve bioprosthesis as part of a Phase I trial. The primary objective was to evaluate the safety, patency, and efficacy of the percutaneous venous valve bioprosthesis to restore competency to the deep venous system.

Adult↗
PubMedDate not supplied

Fate of great saphenous vein after radio-frequency ablation: detailed ultrasound imaging.

Radio-frequency ablation (RFA) of the great saphenous vein (GSV) is an endovascular alternative to stripping. To determine long-term effectiveness, the fate of GSV treated for valvular insufficiency with RFA was evaluated in detail with ultrasound imaging (US). One hundred lower extremities were examined with high-resolution color flow US, an average of 8 months after RFA treatment of an incompetent GSV. For every cm of the RFA-treated segment, the US observation was classified as follows: absent, occluded, or recanalized. Lengths of vein segments in each class were added and percentages of absent, occluded, or recanalized segments were calculated. Five groups were identified. Group I (n = 15): segment of treated GSV was absent. Group II (n = 4): segment of treated GSV was visualized and occluded (these vein segments had no flow and were shrunk and "fibrotic" or thrombosed without clear evidence of significant shrinkage). Group III (n = 1): segment of treated GSV was recanalized. Group IV (n = 27): segment of treated GSV was obstructed (absent or occluded). Group V (n = 53): segment of treated GSV was partially recanalized, on average being 53% absent, 32% occluded, and 15% recanalized. Maximum recanalization was 50% of treated segment. RFA was successful in obliterating all of the GSV treated segment in 46% of veins (groups I, 15%, plus II, 4%, plus IV, 27%) and obliterated more than half of the treated vein segment in 53% of the cases (group V). A dynamic process of recanalization and thrombosis warrants further evaluation to determine if and how a collateral network may develop.

Adult↗
PubMedDate not supplied

Chronic venous insufficiency due to great saphenous vein incompetence treated with radiofrequency ablation: an effective and safe procedure in the elderly.

Chronic venous insufficiency (CVI) with the resultant clinical sequelae significantly reduces quality of life. Most elderly patients with CVI are treated nonoperatively owing to concerns of increased operative risk and therefore suffer more advanced disease. Radiofrequency ablation (RFA) has emerged as a minimally invasive procedure to treat patients with superficial venous insufficiency (SVI) due to great saphenous vein (GSV) incompetence. The purpose of this study was to review our experience using RFA of the GSV to treat CVI due to superficial disease in elderly patients compared to younger patients in terms of procedure-related morbidity and severity of disease at time of treatment. RFA treatment of the GSV was performed in 490 extremities of 421 patients with SVI between March 2001 and December 2002. Indications, medical history, and outcome (operative complications and hospital stay) were compared between 2 groups: Group I:41 extremities of 35 patients, 70 years if age or older (mean 75 +/-4); and Group II:449 limbs of 386 patients younger than 70 years (mean 47 +/-11). The incidence of skin pigmentation and healed/nonhealed ulcers (CEAP 4-6) was significantly higher in the elderly than in the younger group (41% vs 16%, p <0.05). Hypertension, diabetes, and previous myocardial infarction were 2.8, 5.4, and 6.7 times more prevalent in the elderly (p <0.05), respectively. There were no major postoperative complications in either group; 97% of all patients were discharged on the day of operation and there was no difference between the 2 groups in overnight hospital stay. There is a treatment bias against operative management in elderly patients with SVI, as evidenced by their more advanced disease at the time of definitive treatment than their younger cohort. However, operative morbidity is no different compared to the younger subset. RFA is a safe and effective procedure for older patients; therefore, the threshold for operative management of older patients should be lowered.

Age Factors↗
PubMedDate not supplied

Totally subcutaneous hemodialysis access: experience with the LifeSite Hemodialysis System.

The LifeSite Hemodialysis System (Vasca, Inc., Tewksbury, MA) is totally subcutaneous, incorporating two silicone catheters positioned in the central venous system and connected to a stainless steel-titanium valve implanted in a subcutaneous pocket. A randomized trial and nonrandomized clinical experience have demonstrated lower rates of infection and longer device survival when 70% isopropyl alcohol is used as the antimicrobial solution with the LifeSite. Internal jugular vein placement with positioning of the valve on the anterior chest wall further improves results.

2-Propanol↗