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Biomedical subjects

M C Donaldson

Publications and source records attributed to M C Donaldson.

At least 55 records · Page 3Linked to original sources
PubMed1994

Abdominal aortic aneurysms.

The management of abdominal aortic aneurysms has undergone tremendous evolution during the past three decades, resulting in significant advances in our ability to diagnose and safety treat patients with aneurysms. Over the past several years, most research interest has been focused on the etiology of aneurysmal disease, new imaging techniques, cardiac risk stratification, and new approaches for treatment. This article reviews the current approach to diagnosing and treating patients with abdominal aortic aneurysms as well as the results which may be anticipated. In stark contrast to the treatment of nonruptured aortic aneurysms, little progress has been made in the management of ruptured aneurysms, which remain highly lethal. Early identification, prompt evaluation, and surgical repair remain the most important elements in preventing mortality.

Aortic Aneurysm, Abdominal↗
PubMed1993

Further experience with an all-autogenous tissue policy for infrainguinal reconstruction.

PURPOSE: Between 1985 and 1991 a policy of strong preference for autogenous methods of infrainguinal reconstruction was followed to assess the efficacy of this strategy. METHODS: A total of 585 autogenous infrainguinal reconstructions were performed on 537 limbs in 448 patients between 1985 and 1991. Thirty-eight additional revascularizations were performed with prosthetic materials and seven patients underwent primary amputation during this interval. Of the autogenous reconstructions, 74% were primary and 26% were secondary procedures, 71% were for limb salvage, and 48% were to infrapopliteal arteries. Greater saphenous vein was used for 447 bypass grafts. Other autogenous methods included bypass with lesser saphenous (21), arm (20), and composite (30) veins, endarterectomy of the common femoral (18) and superficial femoral (40) arteries, and isolated profundaplasty (9). RESULTS: Major operative morbidity occurred in 41 patients (7%), early graft failure in 47 (8%), and death in 12 (2%). At 5 years, the overall cumulative primary patency rate was 63% and the secondary patency rate was 72%. The 5-year secondary patency rate for the subgroup in which greater saphenous vein was used was 79% and for alternative autogenous methods the rate was 49% (p < 0.001). During the period of follow-up, major amputation was performed in 45 (7.9%) of the operated limbs. CONCLUSION: This experience supports continued preferential use of autogenous methods for infrainguinal reconstruction.

Adult↗
PubMed1993

Infrainguinal reconstruction for patients with chronic renal insufficiency.

PURPOSE: The efficacy of autogenous infrainguinal reconstruction for patients with varying degrees of chronic renal insufficiency was reviewed because it has not been well defined. METHODS: Pertinent data were retrieved from hospital records and the vascular registry for all patients with chronic renal insufficiency (serum creatine > 2 mg/dl) who required surgical intervention for ischemic lower limbs during the past 15 years at Brigham and Women's Hospital. RESULTS: During the past 15 years, 56 patients underwent 70 autogenous vein bypass procedures, and 31 underwent 42 primary major amputations. All patients had serum creatinine levels greater than 2 mg/dl. Limb salvage was the indication for intervention in 84% of reconstructed limbs, and 48% required infrapopliteal bypass. No significant difference was found in the operative mortality rate associated with primary amputation (17%) and reconstruction (11%), but overall 5-year survival for the group undergoing reconstruction (40%) was significantly superior to that observed in the group undergoing amputation (9%). The 5-year cumulative limb salvage rate for the group having reconstruction was 80%, with a primary graft patency of 74% and a secondary patency of 77%. Patients with diabetes had lower rates of both limb salvage (63%) and survival (21%). No patient on dialysis survived beyond the third-year interval, but the limb salvage rate after 2 years was 76%. CONCLUSION: Patients with chronic renal insufficiency achieved graft patency and limb salvage results comparable to those obtained in patients with normal kidney function, but they sustained higher perioperative morbidity and reduced survival.

Adult↗
PubMed1993

Impact of completion angiography on operative conduct and results of carotid endarterectomy.

OBJECTIVE: This study assessed the impact of operative completion angiography on conduct and results of carotid endarterectomy (CEA). SUMMARY BACKGROUND DATA: Completion imaging by angiography, ultrasound or angioscopy reveals occasional residual lesions after CEA. The importance and appropriate management of these lesions remain controversial with respect to operative morbidity and long-term restenosis. METHODS: Carotid endarterectomy was performed 410 times for transient ischemic attack (44%), amaurosis fugax (19%), prior stroke (10%), and asymptomatic carotid stenosis (27%). Routine intraoperative completion angiograms were obtained to exclude significant residual lesions. Postoperative ultrasound follow-up was obtained in 232 patients over a mean interval of 17.3 months. RESULTS: Angiography revealed 71 defects warranting correction in 66 cases (16.1%), including kinks (23), external carotid flaps (18), common carotid plaque (10), thrombus (10), distal internal carotid stenosis (8), intracranial occlusion (1), and spasm (1). Operative morbidity included seven ipsilateral strokes (1.7%) and operative mortality was 0.7%. During follow-up, restenosis > 80% was detected in 17 (7.3%) of 232 arteries, 9 (3.9%) of which underwent reoperation. Rates of restenosis of > 80% were similar between sexes and patched versus unpatched arteries. CONCLUSIONS: Routine completion angiography after CEA guides use of selective operative revision contributing to low rates of perioperative morbidity and restenosis.

Adult↗
PubMed1993

Influence of age on measurement of health status in patients undergoing elective surgery.

PURPOSE: To assess the influence of age on the relationships between global measures of health and specific health dimensions. DESIGN: Cross-sectional cohort study. SETTING: University tertiary care hospital. PATIENTS: Patients older than 50 years admitted for major elective non-cardiac surgery. MEASUREMENTS: Consenting patients underwent preoperative evaluations including a medical history, physical examination, and administration of health status assessment instruments. Global health status was measured with the Medical Outcomes Study Short Form (SF-36) and with a 0 to 100 verbal measure of global health. Specific health dimensions (physical function, role function, social function, mental health, energy and fatigue, and pain) were measured using the SF-36. Subjects also completed a second validated measure of physical functioning, the Specific Activity Scale (SAS). RESULTS: Although patients aged > 70 years (n = 276) had poorer role function, energy, and fatigue scores and poorer physical function on both the SF-36 and SAS than younger patients (n = 469) (P < 0.05), they had similar overall health perception. In the entire population, global health status as measured with the SF-36 health perception scale had the greatest correlation with the energy and fatigue scale (r = .45), correlated moderately with mental health (r = .35), social function (r = .32), and physical function (r = .33), and correlated less well with the surgically remediable dimension of pain (r = .23). However, correlations of global health perception with pain and global health perception with role functioning were significantly (P < or = 0.05) lower in older patients when compared with subjects 70 years or younger (r = .13 vs .28 and r = .19 vs .33, respectively). CONCLUSION: Despite poorer role function, poorer energy and fatigue scores, and poorer physical function, elderly persons have similar global health perception when compared with younger individuals. These data indicate that global health perception may be determined by different factors in the elderly or that the elderly have fundamentally different expectations of what their global health status should be. Our findings emphasize the importance of multidimensional scales when evaluating quality of life because, particularly in the elderly, the use of global measures alone may not reflect critically important dimension-specific impairments in health.

Activities of Daily Living↗
PubMed1993

Carotid endarterectomy: preoperative evaluation of candidates with combined Doppler sonography and MR angiography. Work in progress.

Doppler sonography and magnetic resonance (MR) angiography were prospectively used in combination as a substitute for conventional angiography in 24 consecutive patients likely to undergo carotid endarterectomy. Of 19 patients (20 lesions) who underwent carotid endarterectomy, 18 had not undergone preoperative angiography. High-grade lesions (> 75%-diameter stenosis) were surgically confirmed in 16; a 60%-70% stenosis, in one; and subtotal occlusion of the internal carotid artery, in another. Angiography was performed in a case of suspected internal carotid artery dissection. In the five nonsurgical cases, no significant stenosis was noted with both techniques in two instances, total occlusion was seen in two cases, and an asymptomatic stenosis was seen in one. Follow-up (average, 4.5 months) showed one case of symptomatic occlusion of the internal carotid artery after endarterectomy. This preliminary study suggests that the combined use of Doppler sonography and MR angiography can, in up to 79% (15 of 19) of cases, replace angiography for the preoperative evaluation of patients likely to need carotid endarterectomy.

Aged↗
PubMed1993

Intraarterial thrombolysis of lower extremity occlusions: prospective, randomized comparison of forced periodic infusion and conventional slow continuous infusion.

A prospective randomized controlled trial compared forced infusion (FI) of urokinase (UK) with conventional slow continuous infusion (CI) in 25 patients with 25 acutely ischemic lower limbs. Demographics, ischemia categories, and infusion rates and doses were similar for both groups. A preliminary single-pass bolus of UK was injected into the thrombus in all patients with a pulsed-spray technique, and heparin was administered. UK was then infused with a CI pump (n = 13) or a prototype pulsed-spray pump (n = 12). The primary end point was patency, defined as at least 95% thrombolysis by volume, with brisk antegrade flow occurring within 4 hours. Eleven of the 12 patients (92%) who underwent FI and nine of the 13 (70%) who underwent CI had patency within 4 hours. However, 10 patients who underwent FI and nine who underwent CI had residual thrombi prolonging infusion. No significant differences between the two groups were apparent in speed of lysis, initial success rates, complication rates, or 30-day clinical outcome. Lytic therapy, however, was completed within 24 hours in 18 of 23 (78%) successfully treated patients (P = .01).

Aged↗
PubMed1993

Risks and benefits of femoropopliteal percutaneous balloon angioplasty.

PURPOSE: The purpose of this study was to evaluate the efficacy of angioplasty in the treatment of femoropopliteal arterial disease. METHODS: From 1980 to 1991, 126 angioplasty procedures were performed in 131 limbs of 106 patients with 175 femoropopliteal lesions (26 common femoral, 118 superficial femoral, and 31 popliteal). Critical ischemia was present in 55 limbs (42%), and claudication was present in 76 (58%). Angioplasty was performed for a single lesion in 87 limbs (66%) and for multiple lesions in 44 (34%). In 13 limbs (10%) the most severe lesion was an occlusion; in 118 (90%) all lesions were stenoses. Distal runoff was good (2 or 3 vessels patent) in 72 limbs (55%) and poor (0 or 1 vessel patent) in 59 (45%). RESULTS: Death within 30 days occurred in 0.8%, nonfatal systemic morbidity in 7.1%, and local morbidity in 1.6% of procedures. Multivariate analysis revealed that indication and age were predictive of increased morbidity and mortality rates. Immediate success was achieved in 95% of limbs treated. Mean follow-up time was 2.0 years. The overall 5-year cumulative primary patency rate was 45% (+/- 5%). In a proportional hazards model indication and lesion type were predictive (p < 0.01) of long-term failure, with relative risks of 2.0 (1.2 to 3.3) and 2.7 (1.3 to 5.6), respectively. The 5-year primary patency rate after angioplasty for stenoses and claudication was 55% (+/- 7%), for stenoses and critical ischemia it was 29% (+/- 11%), and for occlusions it was 36% (+/- 14%). CONCLUSION: These results suggest that femoropopliteal angioplasty is a low-risk procedure with acceptable long-term results in patients with claudication and stenoses.

Angioplasty, Balloon↗
PubMed1992

Combined carotid and coronary revascularization: the preferred approach to the severe vasculopath.

The timing of carotid endarterectomy (CEA) and coronary revascularization (CABG) for concomitant disease is controversial. Results of combined CEA/CABG in 127 patients (age range, 46 to 82 years; mean age, 65 years; 61% male) from 1978 to 1991 were reviewed. Ninety-five patients (75%) were in New York Heart Association functional class III or IV, 48 (38%) had left main coronary artery disease, and 32 (28%) had depressed ejection fraction ( < 0.50). Forty (32%) had asymptomatic bruits, 61 (48%) transient ischemic attacks, and 26 (20%) prior strokes. Seventy-five (59%) had bilateral carotid stenosis, including 20 (16%) with contralateral occlusions. Perioperative mortality was 7 of 127 (5.5%), and all deaths were cardiac related. Myocardial infarctions occurred in 6 of 127 patients (4.7%) and were nonfatal in 3 (2.3%). Permanent strokes occurred in 7 of 127 (5.5%) and were ipsilateral in 5 (3.9%). Perioperative stroke did not occur in the asymptomatic group, but the risk was higher in those with prior stroke (19%) or with contralateral carotid occlusion (15%). The stroke risk for our patients with carotid disease having CABG without CEA is not known, but the literature reports rates as high as 14%. For our patients without known concomitant disease, the risk of permanent stroke was 1.0% (31/3012) for isolated CABG and 1.5% (7/482) for isolated CEA. The late results after CEA/CABG revealed a 5-year survival of 70% +/- 5%, which correlated with ejection fraction ( > or = 0.50, 81% +/- 5%; < 0.50, 45% +/- 11%; p < 0.003). Freedom from late permanent ipsilateral stroke was 97% +/- 2% at 8 years. Freedom from stroke at 5 years was lower among patients with a previous stroke (71% +/- 10%) compared with transiently symptomatic (90% +/- 4%) and asymptomatic (96% +/- 4%) patients (p < 0.03). Combined CEA/CABG is a useful option in this high-risk group of patients with extensive atherosclerosis; avoids a subsequent hospitalization, anesthetic, and delay period; and provides long-term protection from ipsilateral stroke.

Actuarial Analysis↗
PubMed1992

Prospective double-blinded comparison of MR imaging and aortography in the preoperative evaluation of abdominal aortic aneurysms.

The authors conducted a prospective double-blind study comparing spin-echo axial and coronal magnetic resonance (MR) imaging with aortography in the preoperative evaluation of 20 patients with abdominal aortic aneurysms. Receiver-operating-characteristic (ROC) analysis was used to evaluate the performance of MR imaging versus aortography in assessing arterial stenotic disease. Both modalities were equivalent in demonstrating the upper extent of the abdominal aortic aneurysms with respect to the renal and visceral arteries. MR imaging was superior in demonstrating aneurysmal iliac arteries and intraluminal thrombus. Although aberrant venous anatomy, associated pathologic changes, and other concomitant lesions were demonstrated with MR imaging, it performed poorly in assessing arterial stenoses and occlusions. Thus, the authors caution against the routine substitution of spin-echo MR imaging for aortography in the evaluation of abdominal aortic aneurysms. Conventional angiography should continue to be performed in patients with suspected mesenteric ischemia, significant hypertension, and symptomatic iliofemoral atherosclerosis, at least until robust MR angiographic techniques have proved themselves under similar rigorous clinical evaluation.

Aged↗
PubMed1992

Causes of primary graft failure after in situ saphenous vein bypass grafting.

In situ saphenous vein bypass grafts originating in the groin were performed in 455 consecutive patients. Primary failure occurred in 92 grafts during follow-up, including 22 (4.8%) with nonocclusive stenosis and 70 (15.4%) with occlusion. The cause for failure could not be determined in seven grafts; 104 contributory causes were identified in the remaining 85 grafts. Among the 104 likely causes, 66 (63%) were intrinsic to the graft itself and contributed to failure of 55 (12.1%) of 455 grafts. These causes included perianastomotic stenosis (48), vein stricture (14), focal vein stenosis (10), valvulotome injury (9), kink (6), retained valve leaflet (4), intimal flap (3), and residual arteriovenous fistula (2). Among these intrinsic causes, 20 were directly related to the in situ technique, contributing to failure of 15 (3.3%) of 455 grafts. Thirty-eight (37%) of the 104 causes were extrinsic to the graft, including compromised inflow (2) or outflow (19), hypercoagulability (9), systemic hypotension (6), and graft sepsis (2). Hypothetically, improvements in technique, patient selection, and perioperative management might have eliminated 46 (44%) of 104 causes of primary graft failure. Delayed graft and anastomotic stenosis and late progression of outflow disease remain resistant to modern therapy.

Aged↗
PubMed1992

Detection of internal carotid artery stenosis: comparison of MR angiography, color Doppler sonography, and arteriography.

Findings of two-dimensional time-of-flight magnetic resonance (MR) angiography projection angiograms were prospectively compared with those of color Doppler sonography by using angiography as a standard in 23 consecutive patients (42 carotid bifurcations) to evaluate their utility in determining the presence of carotid artery stenosis. MR angiography helped detect 50% or greater lumen diameter stenosis (sensitivity, 0.96; specificity, 0.64). Color Doppler sonography with 1.25 m/sec peak systolic velocity as a threshold had a sensitivity of 0.96 and a specificity of 0.71. Statistical analysis showed a correlation between percentage of lumen diameter narrowing and the length of the zone of signal intensity loss with MR angiography (r = .69; P less than .0001). A stronger relationship was obtained between angiographic narrowing and peak systolic velocity derived from color Doppler sonography (r = .80; P less than .0001). Two-dimensional time-of-flight MR angiography displayed as projection angiograms and combined with carotid artery and combined with carotid artery sonography is a useful approach for helping detect and potentially grade the severity of stenoses of the carotid artery.

Aged↗
PubMed1992

The value of cerebral angiography in predicting cerebral ischemia during carotid endarterectomy.

OBJECTIVE: Temporary occlusion of the carotid artery during endarterectomy can result in ipsilateral cerebral ischemia if collateral blood flow is insufficient. This requires placement of a shunt across the carotid bifurcation, which is associated with increased operative risk. We retrospectively analyzed preoperative cerebral angiograms and intraoperative electroencephalographic recordings to determine if ischemia during carotid endarterectomy could be predicted from angiographic data. MATERIALS AND METHODS: The cerebral angiograms of 30 patients were examined. Collateral blood flow to the hemisphere on the side of surgery was determined to be present if both proximal segments of the anterior cerebral artery and the anterior communicating artery were visualized, or if filling and washout of the ipsilateral posterior cerebral artery could be seen. Collateral flow was determined to be inadequate if the anterior collateral system was incomplete, and if either the ipsilateral posterior communicating artery was absent or the posterior cerebral artery filled without washout. This information was compared with intraoperative electroencephalographic and shunting data. RESULTS: Of 15 patients who had demonstrable collateral blood flow, 14 had stable electroencephalograms and did not require a shunt during surgery. In all 15 patients in whom no collateral flow to the ipsilateral hemisphere could be shown, electroencephalographic changes prompted placement of an intraluminal shunt. CONCLUSION: We found that the angiographic determination of inadequate collateral cerebral circulation correlated strongly with the development of intraoperative ischemia. This implies that routine preoperative cerebral angiograms can be used to alert the surgeon to the potential need for shunt placement during carotid endarterectomy.

Aged↗
PubMed1991

Evolving experience with thoracoabdominal aortic aneurysm repair at a single institution.

Fifty-seven patients underwent repair of atherosclerotic thoracoabdominal aortic aneurysms between 1978 and 1990. Five patients had urgent surgery for rupture. The 30-day operative mortality rate for the entire group was 18% (10 patients). Before July 1987, 19 patients (group 1) were operated on by use of a technique previously described. In these earlier patients the peritoneum was routinely entered, the diaphragm was divided radially, and no heparin was given. Among patients in group 1 there was a 30-day operative mortality rate of 42% (8 patients), and morbidity included myocardial infarction 4 (21%), respiratory failure 9 (47%), renal failure 12 (63%), bleeding requiring reoperation 4 (21%), and intestinal ischemia 3 (16%). Since July 1987 a standardized approach to all elective thoracoabdominal aortic aneurysms has been used in 38 patients (group 2). This method uses a left thoracoabdominal incision, circumferential division of the hemidiaphragm, retronephric totally extraperitoneal aortic exposure, single lung anesthesia, full heparinization, the graft inclusion technique, and liberal use of visceral endarterectomy. Patients in group 2 sustained a 30-day operative mortality rate of 5% (2 patients) and morbidity included myocardial infarction 2 (5%), respiratory failure 10 (26%), renal failure 11 (29%), bleeding requiring reoperation 1 (3%), paraplegia 6 (16%), and paraparesis 4 (11%). Modern surgery for repair of thoracoabdominal aortic aneurysm results in acceptably low operative mortality rates. Spinal cord ischemia remains an unresolved source of morbidity.

Aged↗
PubMed1991

Femoral-distal bypass with in situ greater saphenous vein. Long-term results using the Mills valvulotome.

During a 7-year period, 440 consecutive in situ saphenous vein grafts originating in the groin were performed in 371 patients, exposing the entire vein for valvulotomy with a modified Mills valvulotome. critical ischemia was the indication for bypass in 68%, and the distal anastomosis was to an infrapopliteal artery in 46%. Thirty-day operative mortality was 2.0%. Postoperative surveillance identified 18 stenotic grafts (4.1%), which were revised while still patent (primary revised patency); 36 grafts (8.2%) underwent revision after graft occlusion (secondary patency). Five-year life-table analysis showed overall primary revised patency of 78%, secondary patency of 83%, limb salvage of 88%, and patient survival of 66%. Femoroperoneal and inframalleolar bypasses fared well. The presence of diabetes did not diminish late graft patency. In contrast to reversed vein grafts, long infrapopliteal in situ grafts had long-term secondary patency similar to shorter femoropopliteal bypass grafts (p greater than 0.05). These results, coupled with the versatility and simplicity of the technique as used in the present series, suggest that in situ vein grafting is the procedure of choice for long infrapopliteal bypass.

Adult↗
PubMed1991

Limitations of balloon angioplasty for vein graft stenosis.

Vein graft stenosis remains an important contributing factor to the failure of infrainguinal arterial reconstruction. Repair of these lesions before graft occlusion provides sustained patency, yet the optimal method of repair has not been established. Percutaneous transluminal balloon angioplasty of these vein graft lesions has been repeatedly advocated as an alternative to surgical revision. Balloon angioplasty was used in 30 patients with 54 stenotic lesions occurring in autogenous vein grafts after infrainguinal reconstruction. The primary 5-year cumulative patency rate was 18% overall, with no significant differences observed among patency rates based on initial indication, length of stenotic lesion, or requirement for preliminary thrombolytic therapy. The 3-year patency rate associated with vein graft lesions requiring only a single angioplasty proved significantly higher (59%) than those requiring repetitive dilations (6%). It is our conclusion that balloon angioplasty for vein graft stenosis has significant limitations in providing sustained secondary patency.

Adult↗
PubMed1991

Clinical and anatomic considerations for surgery in tibial disease and the results of surgery.

Bypass vein grafts to the infrapopliteal arteries now achieve a 5-year cumulative patency equivalent to that of vein grafts to the popliteal arteries. The technique of in situ vein grafting to the tibial arteries is described and the results are presented. The 5-year cumulative patency for such bypasses and the 5-year limb salvage in the same patients have both been approximately 80%. These results coupled with those reported from other centers that have sizable experience in tibial artery reconstruction suggest that there has been real progress over the past decade in the salvage of lower extremities in patients with far advanced peripheral vascular disease through the use of autogenous venous bypass grafts.

Arteriosclerosis↗