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Biomedical subjects

P G Kalman

Publications and source records attributed to P G Kalman.

At least 19 recordsLinked to original sources
PubMed2003

What are the long-term results of conventional open surgical repair of abdominal aortic aneurysms?

PURPOSE: To determine the long-term results of conventional open surgical repair of abdominal aortic aneurysms (AAAs) and the prevalence of late arterial abnormalities. METHODS: CT scan follow-up was obtained between 8 and 9 years after elective AAA repair on a cohort of patients enrolled in the Canadian Aneurysm Study, a registry that originally consisted of 680 patients. A request for CT follow-up was sent to the responsible surgeon in 1994 when 251 patients were alive and available. Ninety-four of the 251 patients agreed to undergo an abdominal and thoracic CT scan, and each scan was interpreted independently by two vascular radiologists. RESULTS: The aorta was analysed in five defined segments, and an aneurysm was defined as > 50% enlargement from the expected normal value as defined in the Reporting Standards for Aneurysms. Using this strict definition, 64.9% of patients had an aneurysm, but the abnormality was considered a possible indication for surgical repair in 13.8%. Of the 39 patients who had an initial repair with a tube graft, 12 (30.8%) were found to have an iliac aneurysm and 6 (15.4%) were considered to be of possible surgical significance. The median graft size at the time of operation was 18 mm, which increased to a median size of 22 mm at follow-up. Fluid or thrombus around the graft was observed in 28%, and bowel was intimately associated with the graft in 7%. CONCLUSIONS: The longterm results of conventional open surgical repair is durable. CT scan follow-up between 8 and 9 years postoperatively often demonstrates aortic and iliac abnormalities, but the majority are not clinically significant. On the basis of these findings, a routine CT scan of the abdomen and chest is recommended after 5 years. This study provides a population based study for comparison with the longterm results of endovascular repair.

Aged↗
PubMed2000

How do vascular surgeons perceive atherosclerotic risk factor management?

The specific objectives of this report were to determine (1) the usual practice of vascular surgeons with respect to risk factor inquiry and intervention, (2) which risk factors are endorsed by vascular surgeons as being very important in the management of patients with PAD, and, finally, (3) which risk factors vascular surgeons are confident in managing.

Arteriosclerosis↗
PubMed2000

Long-term follow-up of management of failing in situ saphenous vein bypass grafts using endovascular intervention techniques.

PURPOSE: To report the long-term follow-up of previously reported cases of salvaging failing or failed in situ bypass grafts using endovascular techniques, to include previously unreported cases, and to include the results of thrombolysis for the salvage of occluded in situ venous bypass grafts. MATERIALS AND METHODS: Between 1985 and 1995, 352 patients underwent distal bypass via the in situ saphenous vein. Seventy-three of these patients underwent endovascular interventions for (i) graft stenoses (65 lesions in 40 patients) treated by balloon angioplasty (PTA), (ii) AV residual fistulas to veins (AVF) (23 patients) occluded by coil embolotherapy, (iii) graft occlusion (21 occluded grafts in 19 patients) treated by catheter-directed high-dose thrombolytic infusion and PTA or surgical revision of uncovered stenoses, and (iv) retained valve leaflets causing stenoses (five patients) treated by valvectomy and/or PTA. Cumulative patency rates were determined by the Kaplan-Meier method. Twenty-nine of 73 patients had been previously reported by the authors. RESULTS: PTA was successful in 39 of 40 patients, cumulative patency after bypass PTA was 0.79 (SE +/- 0.07) for 12 months and 0.63 (SE +/- 0.12) for 5 years. The only complication of PTA was a graft anastomotic disruption that was successfully treated by surgery. Longer lesions and lesions requiring repeated PTA were more likely to restenose. For thrombolysis, there were 13 of 19 successful infusions and five delayed occlusions. The cumulative patency for both 12 months and 5 years was 0.43 (SE +/- 0.12). AVF embolization was successful in 21 of 23 patients. Cumulative patency for 12 months and 5 years was 0.87 (SE +/- 0.07) and 0.81 (SE +/- 0.09), respectively. Five successful valvectomy procedures were performed by stripping residual valves with endocardial forceps. CONCLUSION: In experienced hands, PTA and AVF embolization can be performed on failing in situ saphenous vein bypass grafts with good long-term patency. Thrombolysis results were less favorable but can prolong patency of grafts.

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PubMed2000

Thoracofemoral bypass: proximal exposure and tunneling.

Although axillobifemoral bypass is the usual alternative to the standard aortobifemoral bypass (ABF) when the latter is contraindicated because of comorbid operative risk or when the transabdominal approach is considered hazardous, a more proximal aortic inflow source is desirable in selected low-risk patients. The results with these more proximal aortic procedures are more durable than with axillobifemoral bypass and approach those that can be achieved with an ABF. This article reviews some of the specific technical details of descending thoracofemoral bypass, specifically, the techniques for proximal exposure and tunneling.

Aorta, Thoracic↗
PubMed1999

Saccular aortic aneurysms.

Most vascular surgeons believe that saccular aortic aneurysms have a more ominous natural history than the typical fusiform aneurysm, although this is not documented in the literature. Expeditious repair is indicated for symptomatic saccular aneurysms, and intervention is usually advocated even when they are asymptomatic because of the general belief that their unique shape predisposes them to rupture. The objective of this report is to review the presentation and surgical management of this uncommon pathology. The records of 10 patients who underwent surgical intervention for an aortic saccular aneurysm between 1985 and 1998 were reviewed. To summarize their presentation and management, we grouped patients according to anatomic location: group A (distal arch), group B (descending thoracic aorta), group C (visceral aorta), and group D (infrarenal aorta). From analysis of these data we conclude that although saccular aortic aneurysms are rare, when present, they are most commonly found in the thoracic and suprarenal aorta. Most cases treated with surgery are symptomatic. Most thoracic and suprarenal saccular aneurysms can be repaired with a patch graft, which spares thoracic intercostals. Repair of saccular aneurysms of the distal arch are only feasible when performed with the use of hypothermic circulatory arrest. Infrarenal saccular aneurysms generally require tube graft replacement because the coexistent atherosclerosis makes patch repair difficult. Endovascular techniques may be the procedure of choice in the future.

Aged↗
PubMed1999

A practical approach to vascular access for hemodialysis and predictors of success.

PURPOSE: The long-term results and predictors of success for vascular access at The Toronto Hospital were studied. This report describes the access program and emphasizes the role of the vascular access coordinator. METHODS: A total of 384 consecutive patients underwent 466 vascular access procedures. The access program is centered around a dedicated, full-time vascular access coordinator, who is a registered nurse and is responsible for all aspects of access care, including follow-up. Outcome variables were collected prospectively. Primary, primary-assisted, and secondary success was determined by means of Kaplan-Meier analysis, and the stepwise Cox proportional hazards model was used for multivariate analysis of the factors that were independently predictive of primary success. RESULTS: There were 235 autogenous arteriovenous fistulae (AVFs) and 231 arteriovenous grafts (AVGs). The cumulative primary, assisted-primary, and secondary success (patent and functional for effective dialysis) at 24 months for all 466 cases combined was 36% +/- 3%, 54% +/- 3%, and 66% +/- 3%, respectively. The primary success for AVFs and AVGs at 2 years was 54% +/- 4% and 18% +/- 4%, respectively (P <.001; log-rank test); the primary-assisted success for AVFs and AVGs at 2 years was 62% +/- 4% and 44% +/- 6%, respectively (P <.001; log-rank test); and the secondary success for AVFs and AVGs at 2 years was 70% +/- 4% and 60% +/- 5%, respectively (P =.331; log-rank test). Stratification of variables revealed significant benefit for AVFs (P =.001), the female sex (P =.014), and the absence of diabetes mellitus (P =.001). Multivariate analysis with Cox regression determined that access type (AVF vs AVG; P =.001) and diabetes mellitus (P =.024) were independently predictive of primary success. The improved clinical coordination of access patients with the initiation of the vascular access program resulted in a significant reduction in length of hospital stay before and after the program was organized (2.5 +/- 0.06 vs 1.1 +/- 0.03 days; P =.001). CONCLUSION: The organization of a vascular access program in a practical and cost-effective way for reduced length of hospital stay is streamlined through a dedicated access coordinator, who ensures an integrated, multidisciplinary approach. The results for the Cox model is useful when discussing the anticipated results of access procedures with individual patients.

Algorithms↗
PubMed1999

The value of late computed tomographic scanning in identification of vascular abnormalities after abdominal aortic aneurysm repair.

PURPOSE: The purpose of this study was to determine the prevalence of late arterial abnormalities after aortic aneurysm repair and thus to suggest a routine for postoperative radiologic follow-up examination and to establish reference criteria for endovascular repair. METHODS: Computed tomographic (CT) scan follow-up examination was obtained at 8 to 9 years after abdominal aortic aneurysm (AAA) repair on a cohort of patients enrolled in the Canadian Aneurysm Study. The original registry consisted of 680 patients who underwent repair of nonruptured AAA. When the request for CT scan follow-up examination was sent in 1994, 251 patients were alive and potentially available for CT scan follow-up examination and 94 patients agreed to undergo abdominal and thoracic CT scanning procedures. Each scan was interpreted independently by two vascular radiologists. RESULTS: For analysis, the aorta was divided into five defined segments and an aneurysm was defined as a more than 50% enlargement from the expected normal value as defined in the reporting standards for aneurysms. With this strict definition, 64.9% of patients had aneurysmal dilatation and the abnormality was considered as a possible indication for surgical repair in 13.8%. Of the 39 patients who underwent initial repair with a tube graft, 12 (30.8%) were found to have an iliac aneurysm and six of these aneurysms (15.4%) were of possible surgical significance. Graft dilatation was observed from the time of operation (median graft size of 18 mm) to a median size of 22 mm as measured by means of CT scanning at follow-up examination. Fluid or thrombus was seen around the graft in 28% of the cases, and bowel was believed to be intimately associated with the graft in 7%. CONCLUSION: Late follow-up CT scans after AAA repair often show vascular abnormalities. Most of these abnormalities are not clinically significant, but, in 13.8% of patients, the thoracic or abdominal aortic segment was aneurysmal and, in 15.4% of patients who underwent tube graft placement, one of the iliac arteries was significantly abnormal to warrant consideration for surgical repair. On the basis of these findings, a routine CT follow-up examination after 5 years is recommended. This study provides a population-based study for comparison with the results of endovascular repair.

Aged↗
PubMed1998

Management of upper extremity central venous obstruction using interventional radiology.

Upper extremity central vein stenosis/occlusion is responsible for significant morbidity. The objective of this report is to review our management using interventional radiological techniques and to determine the long-term clinical results. All radiological interventions for central vein stenosis/occlusion (n = 59) between July 1991 and July 1996 at our institution were reviewed. The interventions consisted of thrombolytic therapy alone in 10 cases, PTA in 40 cases (combined with initial thrombolytic therapy in 6 cases), and deployment of a venous stent in 9 cases. At follow-up, the cumulative success (patency and relief of symptoms) was determined (Kaplan-Meier method). The involved vein was the subclavian, axillary, or innominate (SUB-AX-INN) in 45 cases and the superior vena cava (SVC) in 14 cases. The etiology was secondary to an indwelling foreign body (catheter, pacemaker lead) in 53 cases (90%), and spontaneous in only 6 cases (10%). The average follow-up after intervention was 17.2 months, with a cumulative success of 70 +/- 7.5% at 2 years, with rapid decline thereafter. Analysis of the failure quantiles revealed that 25% failed by 17 months, 50% failed by 26.6 months, and 75% failed by 33.8 months. There were no subgroup differences (log-rank test) for stenosis versus occlusion (p = 0.526), SUB-AX-INN versus SVC (p = 0.744), or if the intervention was begun < 5 days versus > or =5 days after symptom onset (p = 0.240), or whether or not a stent was deployed (p = 0.893). Interventional radiological techniques should be considered when symptoms from upper extremity central vein stenosis/occlusion are severe and disabling, or when veno-access or maintenance of patency of an ipsilateral arteriovenous (A-V) access is necessary. These results suggest an acceptable short-to medium-term solution.

Adult↗
PubMed1998

Mycotic axillary artery aneurysm.

Mycotic axillary aneurysms, not commonly encountered today, are generally the consequence of arterial trauma. A case of an axillary aneurysm secondary to a septic embolus from valvular vegetations in an intravenous drug abuser was studied. The case is reminiscent of those sporadically reported cases of the preanitibiotic era.

Adult↗
PubMed1998

Clinical and pathophysiological effects of active and passive smoking on the cardiovascular system.

Both passive and active cigarette smoking increase the risk of cardiovascular disease, the leading cause of death in Western industrialized nations. The prevalence of smoking as a major cardiovascular risk factor has been well characterized over the past 30 years. The two demographic groups of particular concern are women and the young. The relationship between active tobacco smoking and increased risk of coronary artery disease (stable and unstable angina, acute myocardial infarction or sudden death), cerebrovascular disease (cerebral infarction, and cerebral and subarachnoid hemorrhage), peripheral arterial disease (large and small vessel) and aortic aneurysm has been well established in numerous longitudinal and cross-sectional epidemiological and basic science studies. More recently, passive smoking has been shown to represent an important risk factor for coronary artery disease. Smoking can elicit both acute and chronic cardiac and vascular events due to the multiplicity of mechanisms involved: hematological, neurohormonal, metabolic, hemodynamic, molecular genetic and biochemical pathways. Smoking cessation can result in both the inhibition of progression and the regression of pathophysiological changes, improving morbidity and mortality among chronic smokers. The incidence of coronary artery and cerebrovascular diseases in former smokers decreases by 50% two to three years following cessation, but a small long term excess risk persists. Smoking as a cardiovascular risk factor and the clinical cardiovascular features associated with active and passive smoking are discussed, and a pathophysiological framework to explain the association between cigarette smoking and cardiovascular disease is provided.

Cardiovascular Diseases↗
PubMed1997

Aortic transgraft hemorrhage after systemic thrombolytic therapy.

Aortic transgraft hemorrhage is an unusual complication following thrombolytic therapy that can occur months to years after aortic surgery. It is critical to differentiate this from other potential causes of hemorrhage, such as an acute bleed from an anastomotic false aneurysm which is a surgical emergency. One such case that was managed conservatively with success is reported.

Aged↗
PubMed1997

Predictors of long-term patient survival after in situ vein leg bypass.

PURPOSE: The objective was to determine the long-term survival rates of patients who undergo distal arterial bypass surgery and to identify the preoperative factors that are predictive of survival. METHODS: Three hundred fifty-eight consecutive in situ distal leg bypass procedures were performed between July 1986 and December 1995. The relationship between 13 preoperative variables and late survival were determined using both univariate (Kaplan-Meier) and multivariate (Cox regression) statistical techniques. RESULTS: The cumulative survival rates at 1, 3, 5, and 7 years were 86.6% +/- 2.0%, 63.2% +/- 3.0%, 46.9% +/- 3.4%, and 35.3% +/- 3.8%, respectively. Using Cox regression, four significant variables were found to be associated with lower late survival rates: male gender, diabetes, chronic renal insufficiency (patients with creatinine levels greater than or equal to 1.7 mg/dl or 150 SI units), and a history of cerebrovascular disease (p < 0.001 for model). When none of these four variables were present, the predicted 5-year survival rate was 71%, whereas the survival rate was reduced to 43% to 60% when one was present, 23% to 42% when two were present, 8% to 22% when three were present, and 2% when all four were present. CONCLUSIONS: This study defines the long-term survival rates in a cohort of patients after undergoing distal bypass surgery and demonstrates that certain preoperative factors are predictive of late survival. Knowledge of these factors may be useful to assist in individual operative decisions between aggressive attempts at distal revascularization versus primary amputation.

Aged↗
PubMed1996

Sociologic factors are major determinants of prolonged hospital stay after abdominal aneurysm repair.

BACKGROUND: With increasing pressure to optimize the utilization of hospital resources, it is important to identify patients who may have prolonged hospital length of stay (LOS). The purpose of this report was to identify the preoperative variables that are predictive of prolonged postoperative hospital LOS for patients undergoing elective infrarenal abdominal aneurysm repair and to discuss strategies that might assist in minimizing LOS for these patients. METHODS: Three hundred sixty-five consecutive patients underwent elective infrarenal abdominal aneurysm repair between 1989 and 1994. The relationship between 13 preoperative variables and LOS was analyzed by using both univariate (Kaplan-Meier) and multivariate (Cox regression) statistical techniques. RESULTS: By using Cox regression a model was developed to estimate LOS (p < 0.001 for model). The independent predictors for prolonged LOS were (1) age older than 70 years and (2) absence of a spouse. CONCLUSIONS: Knowledge of the predictive factors that are associated with prolonged LOS should identify those patients who may require prompt and efficient discharge planning, early consultation with a home care nurse, or transfer to a convalescent facility. This approach may significantly improve the utilization of hospital resources.

Age Factors↗
PubMed1995

Mesenteric arterial bypass grafts: early and late results and suggested surgical approach for chronic and acute mesenteric ischemia.

BACKGROUND: The purposes of this study were to determine the early and late results of placement of arterial bypass grafts in the treatment of chronic and acute intestinal ischemia and to ascertain whether multiple grafts provide better late results than a single graft. METHODS: Records of 34 patients who underwent mesenteric vascular graft placement were retrospectively reviewed. RESULTS: All 21 patients with chronic ischemia had a history of intestinal angina and weight loss. Food fear was reported by 33% of patients; also, diarrhea in 57%, constipation in 29%, acalculous cholecystitis in 19%, ischemic gastritis or peptic ulcer in 19%, and elevation of liver enzymes in 22% were reported. Angiogram showed more than 50% stenosis or occlusion of the superior mesenteric artery (SMA) in 100% of patients, celiac artery in 90%, and inferior mesenteric artery in 90%. Although not described previously, a reduction in collateral flow from the internal iliac arteries was caused by severe pelvic disease in 56% of patients. There were no in-hospital deaths. The rate of survival at 1 year was 100%; at 2 years it was 93% +/- 6%, at 3 years 86% +/- 9%, at 5 years 79% +/- 11%, and at 10 years 50% +/- 15%. During follow-up, graft thrombosis occurred in three patients. Of the patients who underwent only a single SMA or celiac bypass, two of five died of bowel infarction; only one of 16 patients who underwent both celiac and SMA bypass had to undergo a repeat surgical procedure because of graft occlusion. Three of 16 retrograde bypasses thrombosed, compared with zero of five prograde bypasses. In nine patients who underwent placement of mesenteric bypass grafts because of acute ischemia caused by acute mesenteric thrombosis, the early mortality rate was 22%; the two deaths were the result of bowel ischemia. The cumulative survival rate was 78% +/- 14% at 1 month, 65% +/- 17% at 1 year, and 52% +/- 16% at 5 years. One of the two late deaths was due to graft thrombosis and bowel infarction. Three of four patients who underwent concomitant mesenteric bypass at the time of aneurysm repair or aortobifemoral bypass survived the surgical procedure. CONCLUSIONS: When chronic and acute mesenteric ischemia are diagnosed and treated with a bypass graft, the early and late results are good. Complete revascularization of the SMA and celiac artery or pelvis or both and prograde bypass may reduce the risk of late bowel ischemia.

Acute Disease↗
PubMed1994

Reversal of delayed-onset paraplegia after thoracic aortic surgery with cerebrospinal fluid drainage.

We report two patients who had postoperative reversal of delayed-onset paraplegia after cerebrospinal fluid (CSF) drainage after type I thoracoabdominal aneurysm repair. CSF drainage was not initiated before operation because of the urgent presentation of both patients. Decompression of the spinal canal by CSF drainage may improve spinal cord circulation in certain patients and may avoid or decrease neurologic injury. In view of the low morbidity of this intervention, we recommend routine CSF drainage during elective repair of thoracic and thoracoabdominal aneurysms.

Aged↗
PubMed1994

Preoperative factors that predict hospital length of stay after distal arterial bypass.

PURPOSE: The purpose of this study was to identify the preoperative factors that are predictive of prolonged hospital length of stay (LOS) and to discuss strategies that might assist in minimizing LOS for this select group of patients. METHODS: Two hundred seventy-five arterial bypass procedures with the in situ technique were performed between 1986 and 1993. The relationship between 14 preoperative variables and hospital LOS was analyzed with both univariate (Kaplan-Meier) and multivariate (Cox regression) statistical techniques. A model was developed to determine the significant preoperative variables that were associated with prolonged LOS. RESULTS: The primary and secondary patency rates and limb salvage rates at 4 years were 73.3% +/- 3.2%, 78.9% +/- 2.9%, and 81.9% +/- 3.2%, respectively. The median postoperative LOS was 15 days, with a mean +/- SD of 17.8 +/- 12.3 days (range 4 to 93 days). With Cox regression analysis, the variables that were significant predictors of LOS (with a model p value < 0.002) were age (greater than 74 years vs less than 75), history of cerebrovascular disease (transient ischemic attack, stroke, past carotid endarterectomy vs nil), and operative indication (limb salvage vs disabling claudication). CONCLUSIONS: This study illustrates that certain preoperative variables are predictive of prolonged postoperative LOS after in situ bypass. The significant preoperative factors identified should be used to direct specific care and discharge planning for these individuals.

Aged↗