Nondialysis Dependent Renal Insufficiency Research Articles

5878Renal insufficiency is associated with progressive increase in risk of cardiovascular death in patients without preexisting cardiovascular disease

Abstract Introduction and aims Chronic kidney disease has previously been observed to be associated with increased cardiovascular risk. Observations are however predominantly limited to patients with either severe or end-stage renal disease. We investigate the associated risk of diminishing renal function with cardiovascular death across all levels of non-dialysis dependent renal insufficiency. Methods Based on cross-referencing of data from numerous nationwide health care registers, patients with a recorded plasma creatinine measurement were identified in Denmark between 1997 and 2017. Patients with preceding cardiovascular disease, end-stage renal disease, age <18 years, and patients with events within a 30 days quarantine period after their first-time plasma creatinine measurement were excluded. Estimated glomerular filtration rates (eGFRs) were calculated from the first recorded plasma creatinine. Hazard ratios for two-year risk of cardiovascular death were computed for strata of renal function in a multiple Cox regression model with adjustment for age and gender, and cumulative incidences were estimated using the Aalen-Johansen estimator. Results In total 2,000,626 patients were identified. Median follow-up was 3.6 years (IQR 1.7–9.0 years). A total of 22,657 (0.01%) cardiovascular deaths were recorded. Patients were predominantly female (54%), median age was 40 years (IQR 29–63 years), and median eGFR was 98 ml/min/1.73m2 (IQR 83–117 ml/min/1.73m2). Hazard ratios with confidence intervals of cardiovascular death were 0.85 [0.82–0.89], 1.24 [1.18–1.31], 2.02 [1.89–2.15], and 3.19 [2.91–3.49] for the eGFR strata 90–60 ml/min/1.73m2, 59–45 ml/min/1.73m2, 44–30 ml/min/1.73m2, <30 ml/min/1.73m2, respectively (eGFR >90 ml/min/1.73m2 as reference). Cumulative incidence Conclusion In a nationwide cohort of non-dialysis treated patients without pre-existing cardiovascular disease, renal dysfunction was associated with progressive increase in risk of cardiovascular death in patients with eGFR <60 ml/min/1.73m2.

Off-Pump Coronary Revascularization preserves Renal Function in patients with Preoperative Non-Dialysis dependent renal dysfunction - A Prospective, Randomized Study

The off-pump coronary artery bypass operation (OPCAB) is a relatively new surgical procedure, which avoids the use of cardiopulmonary bypass and is intuitively considered renoprotective in patients with preoperative normal renal function. However, no prospective, randomized study has been done so far to show whether these benefits may also apply to patients with preoperative non-dialysis dependent renal dysfunction. This first ever prospective, randomized, controlled trial was performed in 50 patients (45 men, mean age 51.2±4.8 yrs) with preoperative nondialysis dependent renal insufficiency, undergoing first-time elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on-pump) or beating heart revascularization (off-pump). Glomerular and tubular functions were assessed upto 48 hrs postoperatively. There were no deaths, strokes or myocardial infarctions in either group. Glomerular function as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on-pump group (p=0.0003 and p=0.008, respectively). Renal tubular function was also significantly impaired in the on-pump group as assessed by the increased N- acetyl glucosaminidase activity (p=0.021). Six patients in the on-pump group developed acute renal failure requiring renal support compared with one in the off-pump group although statistically the comparison was not significant (p=0.098). This study suggests that off-pump coronary artery bypass surgery reduces the likelihood of acute renal failure in patients with preoperative non-dialysis dependent renal dysfunction and thus shortens postoperative intensive care and length of hospital stay.

Cardiovascular Surgery with Cardiopulmonary Bypass in Patients with Preoperative Non-dialysis Dependent Renal Insufficiency.

Preoperative renal insufficiency is a predictor of acute renal injury in patients undergoing cardiovascular surgery with cardiopulmonary bypass. From January 2010 to September 2012, 121 patients undergoing coronary bypass, valve replacement, or both were included in our retrospective study, using cardiopulmonary bypass. We compared the changes in renal function and clinical outcomes of 66 patients with a baseline serum creatinine level more than 1.5 mg/dL with 55 patients with normal serum creatinine levels. We analyzed the impact of cardiopulmonary bypass in patients with non-dialysis dependent renal insufficiency. In the group of patients with preoperative renal injury, the need for dialysis was greater, time of mechanical ventilation longer, and daily diuresis lesser compared with the group of patients with normal serum creatinine levels. Other clinical outcomes such as postoperative hemodynamic problems and organ dysfunction were similar. Prolonged time of cardiopulmonary bypass and cross-clamp affected postoperative renal injury. The study also showed intraoperative dopamine infusion at renal dose and ultrafiltration are not effective with protecting renal tubular function. Serum creatinine levels and glomerular filtration rate (GFR) were found to be useful parameters for renal injury. These results demonstrate the safety and trustworthiness of cardiopulmonary bypass in patients with non-dialysis dependent renal insufficiency.

Heart and Combined Heart–Kidney Transplantation in Patients With Concomitant Renal Insufficiency and End-Stage Heart Failure

In patients with end-stage heart failure (ESHF) who are candidates for isolated heart transplant (HRT), dialysis dependence (DD) is considered an indication for combined heart-kidney transplantation (HKT). HKT remains controversial in ESHF transplant candidates with nondialysis-dependent renal insufficiency (NDDRI). Using United Network for Organ Sharing data, we examined the cumulative incidences of transplant and mortality in patients with DD and NDDRI waitlisted for HKT or HRT. In all groups, 3-month waitlist mortality was dismal: 31% and 21% for HRT- and HKT-listed patients with DD and 12% and 7% for HRT- and HKT-listed patients with NDDRI. Five-year posttransplant survival was improved in HKT recipients compared with HRT recipients for both patients with DD (73% vs. 51%, p<0.001) and NDDRI (80% vs. 69%, p<0.001). Likewise, multivariable analysis associated HKT with better outcomes than HRT in HKT-listed patients, although both improved survival. These data argue strongly for HKT in ESHF transplant candidates with DD. However, in patients with NDDRI, HKT must be weighed against the possibility of renal recovery with isolated HRT. Whether HRT (followed by a staged kidney transplant in patients who do not recover renal function after HRT), as opposed to HKT, maximizes organ benefit for patients with NDDRI and ESHF requires assessment. Nevertheless, given their dismal waitlist outcomes and excellent posttransplant results, we suggest that patients with DD and NDDRI with ESHF be considered for early listing and transplant.

Coronary artery bypass grafting with or without cardiopulmonary bypass in patients with preoperative non–dialysis dependent renal insufficiency: A randomized study

Preoperative renal insufficiency is a predictor of acute renal failure in patients undergoing coronary artery revascularization with cardiopulmonary bypass. Off-pump coronary artery bypass grafting has been shown to be less deleterious than on-pump bypass in patients with normal renal function, but the effect of this technique in patients with non-dialysis dependent renal insufficiency in a randomized study is unknown. From August 2004 through October 2005, 116 consecutive patients with preoperative non-dialysis-dependent renal insufficiency (glomerular filtration rate measured using the Modification of Diet in Renal Disease equation [MDRD GFR] < or = 60 mL x min(-1) x 1.73 m(-2)) undergoing primary coronary artery bypass grafting were randomized to on-pump (n = 60) and off-pump (n = 56) groups. MDRD GFR and serum creatinine levels were measured preoperatively and postoperatively at days 1 and 5. The changes in renal function and clinical outcomes were compared between the two groups. Preoperative characteristics were comparable between the two groups. The repeated-measures analysis of variance was performed on the data that showed worsening of renal function in the on-pump group compared with the off-pump group (serum creatinine, P < .000; glomerular filtration rate, P < .000). Further analysis of subgroups of patients with diabetes alone, hypertension alone, and combined hypertension and diabetes also showed significant deterioration renal function in the on-pump group compared with the off-pump group. In covariate analysis, diabetes has emerged as a significant covariate by serum creatinine criteria while compromised left ventricular function has emerged as a significant covariate by glomerular filtration rate criteria. These analyses showed that the use of cardiopulmonary bypass is significantly associated with adverse renal outcome (P < .000). Three patents required hemodialysis in the on-pump group and none in the off-pump group. The mean number of grafts per patient was 3.85 +/- 0.86 and 3.11 +/- 0.89 in the on-pump and off-pump groups, respectively (P < .001), but the indices of completeness of revascularization, 1.00 +/- 0.08 for off-pump coronary bypass and 1.01 +/- 0.08 for on-pump coronary bypass, were similar (P = .60). This study suggests that on-pump as compared with off-pump coronary artery bypass grafting is more deleterious to renal function in diabetic patients with non-dialysis dependent renal insufficiency. MDRD GFR is a more sensitive investigation than serum creatinine levels to assess renal insufficiency in patients undergoing coronary bypass.

The significance of elevated troponin T in patients with nondialysis‐dependent renal insufficiency: A validation with coronary angiography

Patients with elevated troponin are at high risk of adverse outcomes, future cardiac events, and are more likely to have hemodynamically significant coronary artery stenoses. Elevated troponin T (cTnT) in patients with poor renal function portends a poor prognosis; however, findings of significant coronary artery disease (CAD) by coronary angiography have not been demonstrated in patients with poor renal function and elevated cTnT. The purpose of this study was to correlate the angiographic findings of patients with elevated cTnT with respect to renal function in patients with nondialysis-dependent renal insufficiency. We retrospectively identified 342 patients with elevated cTnT who underwent coronary angiography in the setting of acute coronary syndrome. Patients were divided into poor (< 40 ml/min) and normal (> 40 ml/min) renal function by measuring their glomerular filtration rate. Our primary outcome was CAD stenosis, defined as epicardial stenosis > or = 70%. Secondary outcomes were rates of contrast nephropathy, initiation of hemodialysis, revascularization, length of stay (LOS), and in-hospital mortality. There was no significant difference in the prevalence of CAD between patients who had positive cTnT with poor renal function versus patients with positive cTnT and normal renal function (87.1 vs. 89.7%, p = 0.54). This finding persisted after stratifying by age. Patients with impaired renal function had a higher mortality, longer LOS, and a higher rate contrast nephropathy requiring hemodialysis. The association between elevated cTnT and significant CAD stenosis does not vary with renal function.

Impact of renal insufficiency on short- and long-term outcomes after cardiac surgery

Abstract Background Renal insufficiency is highly prevalent in North America and has been established as a nontraditional risk factor for cardiovascular disease. Cardiovascular disease remains the primary cause of mortality in the general population and is often treated with coronary artery bypass surgery (CABG). This population-based study aimed to determine the risk of nondialysis dependent renal insufficiency (RI) on the long-term outcomes of patients who undergo CABG. Methods Prospectively collected data from 26,506 patients were abstracted from the Cardiac Care Network database from 9 revascularization hospitals in Ontario, Canada. Multivariate regression analysis examined associations between preoperative RI and inhospital, 30-day, and 1-year mortality according to 3 levels of serum creatinine: 180 μmil/L (moderate-severe RI) and 5 levels of creatinine clearance (Cockcroft-Gault): >100 mL/min (normal), 80 to 99 mL/min (mild impairment), 60 to 79 mL/min (mild-moderate impairment), 40 to 59 mL/min (moderate impairment), and Results The overall inhospital, 30-day, and 1-year mortality rates were 1.90%, 2.0%, and 4.5%, respectively. Patients with RI had greater overall comorbidity. After adjustment for confounding factors, RI was associated with the greater risk of both 30-day (odds ratio 3.7, 95% CI 2.3–5.8, P P Conclusion Preoperative renal impairment should be recognized as a significant risk factor for mortality after CABG. A trend of increasing risk with severity of renal impairment was demonstrated for both 30-day and 1-year mortality in this large, population-based study.

Impact of renal insufficiency on short- and long-term outcomes after cardiac surgery

Background Renal insufficiency is highly prevalent in North America and has been established as a nontraditional risk factor for cardiovascular disease. Cardiovascular disease remains the primary cause of mortality in the general population and is often treated with coronary artery bypass surgery (CABG). This population-based study aimed to determine the risk of nondialysis dependent renal insufficiency (RI) on the long-term outcomes of patients who undergo CABG. Methods Prospectively collected data from 26,506 patients were abstracted from the Cardiac Care Network database from 9 revascularization hospitals in Ontario, Canada. Multivariate regression analysis examined associations between preoperative RI and inhospital, 30-day, and 1-year mortality according to 3 levels of serum creatinine: <120 μmol/L (normal), 120 to 180 μmol/L (mild RI), and >180 μmil/L (moderate-severe RI) and 5 levels of creatinine clearance (Cockcroft-Gault): >100 mL/min (normal), 80 to 99 mL/min (mild impairment), 60 to 79 mL/min (mild-moderate impairment), 40 to 59 mL/min (moderate impairment), and <40 mL/min (severe impairment). Results The overall inhospital, 30-day, and 1-year mortality rates were 1.90%, 2.0%, and 4.5%, respectively. Patients with RI had greater overall comorbidity. After adjustment for confounding factors, RI was associated with the greater risk of both 30-day (odds ratio 3.7, 95% CI 2.3–5.8, P < .0001) and 1-year mortality (odds ratio 4.6, 95% CI 3.3–6.4, P < .0001). Conclusion Preoperative renal impairment should be recognized as a significant risk factor for mortality after CABG. A trend of increasing risk with severity of renal impairment was demonstrated for both 30-day and 1-year mortality in this large, population-based study.

On-pump versus off-pump coronary artery bypass grafting: impact on postoperative renal failure requiring renal replacement therapy

Background Despite refinements in perioperative patient management postoperative renal failure requiring hemofiltration or dialysis is still a common complication after coronary artery bypass grafting associated with impaired patient outcome. Methods Prospective data on 9,631 patients receiving myocardial revascularization with (coronary artery bypass grafting [n = 8,870]) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting [n = 761]) between April 1996 and August 2001 were evaluated by univariate and multivariate logistic regression analysis. Results Overall prevalence of postoperative continuous renal replacement therapy was 4.1% (coronary artery bypass grafting, 4.3%; off-pump coronary artery bypass grafting, 1.8%; p = 0.001). Thirty of 40 selected preoperative and intraoperative patient and treatment related variables had a high association with the requirement for postoperative renal replacement therapy; fifteen of these variables were independent predictors in the whole study population. Off-pump coronary artery bypass surgery was identified as having a significantly lower predictive value for postoperative continuous renal placement therapy. In the subgroup of patients undergoing off-pump coronary artery bypass grafting surgery, a second multivariate logistic regression model revealed preoperative cardiogenic shock, urgent operation, intraoperative low cardiac output, and high transfusion requirement as independent predictors for postoperative renal replacement therapy. Conclusions Patients with preoperative nondialysis dependent renal insufficiency are at a high risk for further decline in renal function requiring postoperative continuous renal replacement therapy. Off-pump coronary artery bypass surgery is associated with a lower prevalence of postoperative renal replacement therapy after coronary artery bypass grafting.

Coronary revascularization with or without cardiopulmonary bypass in patients with preoperative nondialysis-dependent renal insufficiency

Background. Preoperative renal insufficiency is a predictor of acute renal failure in patients undergoing conventional coronary artery bypass grafting. Off-pump coronary artery bypass operations have been shown to reduce renal dysfunction in patients with normal renal function, but the effect of this technique in patients with preoperative nondialysis-dependent renal insufficiency is unknown. Methods. From June 1996 to December 1999, data of 3,250 consecutive patients undergoing coronary artery bypass grafting were prospectively entered into the Patient Analysis & Tracking Systems (PATS, Dendrite Clinical Systems, London, UK). Two hundred and fifty-three patients with preoperative serum creatinine more than 150 μmol/L were identified (202 patients on-pump, 51 patients off-pump), and clinical outcomes were analyzed. Serum creatinine and urea, in-hospital mortality, and morbidity were compared between groups. The association of perioperative factors with acute renal failure was investigated by multiple logistic regression analysis. Results. Preoperative characteristics were similar between the groups. Mean number of grafts was 2.9 ± 0.8 and 2.3 ± 0.8 in the on-pump and off-pump groups, respectively ( p < 0.0001). Comparison between groups showed a significantly higher incidence of stroke, inotropic requirement, blood loss, and transfusion of red packed cell and platelets in the on-pump group (all p < 0.05). Postoperative serum creatinine and urea were higher in the on-pump group with a significant difference at 12 hours postoperatively ( p < 0.05). Logistic regression analysis identified cardiopulmonary bypass, serum creatinine level 60 hours postoperatively, inotropic requirement, need for intraaortic balloon pump, transfusion of red packed cell, and hours of ventilation as predictors of postoperative acute renal failure. Conclusions. This study suggests that off-pump coronary artery bypass operations reduce in-hospital morbidity and the likelihood of acute renal failure in patients with preoperative nondialysis-dependent renal insufficiency undergoing myocardial revascularization.

Poor Long-Term Survival After Coronary Angiography in Patients With Renal Insufficiency

Cardiovascular disease is common among dialysis patients, but much less is known regarding non-dialysis-dependent renal insufficiency (NDDRI) and its association with cardiac disease. We undertook a study to assess the impact of renal insufficiency on survival post-coronary angiography by comparing three groups of patients: dialysis-dependent patients, patients with NDDRI (creatinine > 2.3 mg/dL), and a reference group with creatinine levels less than 2.3 mg/dL and not on dialysis therapy. We used a prospective cohort that consisted of all patients undergoing coronary angiography in Alberta, Canada, from January 1, 1995, to December 31, 1997. Of the 16,989 patients, 196 patients (1.2%) were on dialysis therapy, 262 patients (1.5%) had NDDRI, and 16,531 patients (97.3%) formed the reference group. Mortality rates 1 year after angiography were 30.2% for patients with NDDRI, 15.8% for dialysis patients, and 4.1% for the reference group. Compared with the reference group, crude 4-year survival was significantly worse for dialysis patients and those with NDDRI, with hazard ratios of 4.05 (95% confidence interval, 3.02 to 5.42) and 7.32 (95% confidence interval, 5.97 to 8.97), respectively. Even after adjusting for clinical risk factors, survival remained worse for dialysis patients and those with NDDRI, with hazard ratios of 2.59 (95% confidence interval, 1.92 to 3.49) and 2.51 (95% confidence interval, 2.02 to 3.12), respectively. We conclude that renal insufficiency, both dialysis dependent and non-dialysis dependent, is an independent risk factor for increased mortality and poor long-term survival among patients undergoing coronary angiography.

Is Renal Insufficiency an Atherogenic State? Reflections on Prevalence, Incidence, and Risk

○ Cardiovascular disease is common among dialysis patients, but much less is known regarding non-dialysis-dependent renal insufficiency (NDDRI) and its association with cardiac disease. We undertook a study to assess the impact of renal insufficiency on survival post-coronary angiography by comparing three groups of patients: dialysis-dependent patients, patients with NDDRI (creatinine > 2.3 mg/dL), and a reference group with creatinine levels less than 2.3 mg/dL and not on dialysis therapy. We used a prospective cohort that consisted of all patients undergoing coronary angiography in Alberta, Canada, from January 1, 1995, to December 31, 1997. Of the 16,989 patients, 196 patients (1.2%) were on dialysis therapy, 262 patients (1.5%) had NDDRI, and 16,531 patients (97.3%) formed the reference group. Mortality rates 1 year after angiography were 30.2% for patients with NDDRI, 15.8% for dialysis patients, and 4.1% for the reference group. Compared with the reference group, crude 4-year survival was significantly worse for dialysis patients and those with NDDRI, with hazard ratios of 4.05 (95% confidence interval, 3.02 to 5.42) and 7.32 (95% confidence interval, 5.97 to 8.97), respectively. Even after adjusting for clinical risk factors, survival remained worse for dialysis patients and those with NDDRI, with hazard ratios of 2.59 (95% confidence interval, 1.92 to 3.49) and 2.51 (95% confidence interval, 2.02 to 3.12), respectively. We conclude that renal insufficiency, both dialysis dependent and non-dialysis dependent, is an independent risk factor for increased mortality and poor long-term survival among patients undergoing coronary angiography.

Impact of transrenal aortic endograft placement on endovascular graft repair of abdominal aortic aneurysms

Purpose: Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. Methods: Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. Results: There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts ( P ≤.05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (≥50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. Conclusion: Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion. (J Vasc Surg 1998;28:638-46.)

Renovascular hypertension in the elderly: Results of surgical management

This review summarizes our experience with the operative management of renovascular hypertension (RVH) in elderly patients (≥ 60 years of age). From 7/87 through 6/95,230 of 428 adult patients (54%) undergoing operation of renovascular hypertension at our center were in their seventh (153 patients), eighth (70 patients) or ninth (7 patients) decade of life (mean age: 68 years). There were 117 males and 113 females with blood pressures ranging from 280/190 to 178/90 (mean: 202/102 mmHg). One hundred and eighty patients (78%) had renal insufficiency (i.e., serum creatinine ≥ 1.3 mg/dl). One hundred and four patients (45 %) had severe insufficiency (i.e., serum creatinine ≥2.0 mg/dl), with 23 of these patients being dialysis dependent prior to operation. Two hundred and eighteen (95%) had evidence of organ specific atherosclerotic damage as manifested by cardiac disease (93%), cerebrovascular disease (38%) or renal insufficiency (78%). Operative management consisted of a unilateral procedure in 100 patients, bilateral procedures in 130 patients, including 26 nephrectomies. Simultaneous aortic replacement was performed in 95 patients (41%; 59 AAA and 36 occlusive disease). After surgery, there were 13 operative deaths (6%) and 13 renal artery repairs failed (4%). Hypertension was cured (9%) or improved (77%) in 86% of operative survivors. Renal function was improved in 43% and worsened in 15% of patients with nondialysis dependent renal insufficiency. Eighteen of twenty-three patients (78%) who were dialysis dependent before surgery were removed from dialysis following renal revascularization. On follow-up (mean: 29 months), we found that 28 patients died. Multivariate analysis demonstrated that preoperative congestive heart failure (p = 0.007) and increased serum creatinine (p = 0.001) were significant and independent predictors of death on follow-up. Estimated survival was significantly increased among patients with improved renal function after operation compared with patients unimproved. This review emphasizes the complexity of atherosclerosis in the elderly population presenting for operative management of renovascular hypertension. Despite the complexity of disease, our experience suggests that operative management is beneficial and can be accomplished with acceptable, albeit increased, risk in properly selected elderly patients. For elderly patients with renovascular disease in combination with renal insufficiency (i.e., ischemic nephropathy), improved renal function after operation may convey improved survival.

Carbon Dioxide Digital Subtraction Arteriography: A Pilot Study

To investigate the diagnostic value of carbon dioxide arteriograms in patients with peripheral vascular disease, ten patients in whom standard contrast arteriography was contraindicated underwent carbon dioxide digital subtraction arteriography. Lower extremity ischemia or severe hypertension with renal insufficiency were the indications for arteriography. Standard contrast arteriography was precluded by chronic nondialysis-dependent renal insufficiency, severe congestive heart failure or contrast hypersensitivity. All critical arterial segments were well visualized with the exception of the infrapopliteal arterial tree in three patients. Adequate imaging of this segment required the addition of 20 cc of dilute nonionic contrast. Guided by carbon dioxide digital subtraction arteriography, four percutaneous transluminal angioplasties and three reconstructive procedures were successfully performed. One patient did not have surgically reconstructible disease and two had renal arteries without critical stenoses. Renal function transiently deteriorated in one patient who received 20 cc of nonionic contrast. No adverse events occurred due to carbon dioxide. Clinically useful diagnostic arteriograms are possible using carbon dioxide as the contrast agent.