Thomas N. Skelton

Contrast Nephrotoxicity: A Randomized Controlled Trial of a Nonionic and an Ionic Radiographic Contrast Agent

Experimental studies have suggested that nonionic contrast agents are less nephrotoxic than ionic contrast agents. To examine the relative nephrotoxicity of the two types of agents, we randomly assigned 443 patients to receive either iopamidol (nonionic) or diatrizoate (ionic) for cardiac catheterization. The patients were stratified into low-risk (n = 283) or high-risk (n = 160) groups, on the basis of the presence of diabetes mellitus, heart failure, or preexisting renal insufficiency (base-line serum creatinine level, greater than 133 mumol per liter). Serum and urine analyses were performed at base line and 24 and 48 hours after the infusion of contrast material. Nephrotoxicity was defined as an increase in the serum creatinine level within 48 hours of at least 44 mumol per liter. The median maximal rise in the serum creatinine level was 18 mumol per liter in both the diatrizoate group (n = 235) and the iopamidol group (n = 208) (P not significant; power to detect a difference greater than 9 mumol per liter, greater than 90 percent). Creatinine levels increased by at least 44 mumol per liter (0.5 mg per deciliter) in 10.2 percent of the patients receiving diatrizoate and 8.2 percent of the patients receiving iopamidol (P not significant). Among the high-risk patients, creatinine levels increased by at least 44 mumol per liter in 17 percent of the patients in the diatrizoate group, as compared with 15 percent of the patients in the iopamidol group (P not significant). We were unable to demonstrate a difference in the incidence of nephrotoxicity between patients receiving a non-ionic contrast agent and those receiving an ionic contrast agent.

Cardiovascular and Renal Toxicity of a Nonionic Radiographic Contrast Agent after Cardiac Catheterization: A Prospective Trial

STUDY OBJECTIVE To determine the incidence of cardiovascular and renal toxicity of a nonionic contrast agent when used for cardiac catheterization, and to assess the value of electrolytes and urinalysis results as predictors of nephropathy induced by a contrast agent. STUDY DESIGN Nonrandomized trial using a criterion standard and a cohort analytic study with a 48-hour follow-up. SETTING Referral-based university hospital. PATIENTS Convenience sample of patients having diagnostic cardiac catheterization. Renal function and clinical status were evaluated at baseline in 1,144 patients; at 24 hours in 1,077 (94%); and at 48 hours in 663 (57%). INTERVENTIONS After patients received saline for hydration, coronary angiography and left ventriculography were done with iopamidol (average dose, 203 +/- 56 cc). MEASUREMENTS AND MAIN RESULTS The definite and possible incidence of major acute cardiovascular complications from nonionic contrast media was 0.2% and 0.7%, respectively. The mean serum creatinine level increased 11.5 mumol/L from baseline at 24 hours (P less than 0.0001) and 16.8 mumol/L from baseline at 48 hours (P less than 0.0001). Results in a randomly selected training sample were studied to determine predictors of a rise in serum creatinine of 44.2 mumol/L or more. The baseline serum creatinine level and age were significant predictors of renal injury, but hypertension, diabetes mellitus, congestive heart failure, vascular disease, the volume of contrast agent injected or baseline values of urinary variables did not predict nephrotoxicity. In an independent validation sample, only the baseline serum creatinine level was confirmed as a predictor of nephrotoxicity, whereas age was not. A model that predicted contrast-induced nephropathy by the serum creatinine level showed an exponential increase in the risk for nephrotoxicity if the baseline level was 106.1 mumol/L or higher. CONCLUSIONS Patients have a small but significant rise in serum creatinine after cardiac catheterization with a nonionic contrast agent. Baseline renal insufficiency is the only confirmed predictor of nonionic contrast-induced nephrotoxicity.

Comparison of preload recruitable stroke work, end-systolic pressure-volume and dPdtmax-end-diastolic volume relations as indexes of left ventricular contractile performance in patients undergoing routine cardiac catheterization☆

The end-systolic pressure-volume relation, the relation between stroke work and end-diastolic volume, termed the preload recruitable stroke work relation, and the relation between the peak of the first derivative of left ventricular pressure (dP/dtmax) and end-diastolic volume have been employed as linear indexes of left ventricular contractile performance in laboratory animals. The purpose of this study was to examine the relative utility of these indexes during routine cardiac catheterization in seven human subjects (mean age 48 +/- 18 [SD] years) with a normal left ventriculogram and coronary angiogram. Left ventricular pressure was recorded continuously with a micromanometer catheter, and left ventricular volume was derived from digital subtraction contrast ventriculograms obtained at 30-ms intervals. Transient occlusion of the inferior vena cava with a balloon-tipped catheter was employed to obtain beat to beat reductions in left ventricular pressure and volume over 8.7 +/- 1.7 cardiac cycles. Stroke work declined by 49 +/- 13% during vena caval occlusion, but end-systolic pressure fell by only 26 +/- 11%, and changes in dP/dtmax were small and inconsistent (12 +/- 22%). Consequently, the range of data available for determination of the preload recruitable stroke work relation greatly exceeded that for the end-systolic pressure-volume relation and the dP/dtmax-end-diastolic volume relation, and much less linear extrapolation from the measured data was required to determine the volume-axis intercept. Preload recruitable stroke work relations were highly linear (r = 0.95 +/- 0.07), and much more so than end-systolic pressure-volume relations (r = 0.79 +/- 0.23).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise treadmill testing is a poor predictor of anatomic restenosis after angioplasty for acute myocardial infarction.

This study evaluated whether an exercise treadmill test could predict restenosis in 289 patients 6 months after a successful emergency angioplasty of the infarct-related artery for acute myocardial infarction. After excluding those with interim interventions (64), medical events (36), or medical contraindications to follow-up testing (25), both a treadmill test and a cardiac catheterization were completed in 144 patients, 88% of those eligible for this assessment. Four patients with left bundle branch block or pacemaker rhythm at the time of treadmill testing were also excluded from analysis. Of six follow-up clinical and treadmill variables examined by multivariable logistic regression analysis, only exercise ST deviation was independently correlated with restenosis at follow-up (chi 2 = 5, p = 0.02). The clinical diagnosis of angina at follow-up, although marginally related to restenosis when considered by itself (p = 0.04), did not add significant information once ST deviation was known. The sensitivity of ST deviation of 0.10 mV or greater for detecting restenosis was only 24% (13 of 55 patients), and the specificity was 88% (75 of 85 patients). The sensitivity of exercise-induced ST deviation for detection of restenosis was not affected by extent or severity of wall motion abnormalities at follow-up, by the timing of thrombolytic therapy or of angioplasty, or by the presence of collateral blood flow at the time of acute angiography. A second multivariable analysis evaluating the association of the same variables with number of vessels with significant coronary disease at the 6-month catheterization found an association with both exercise ST deviation (p = 0.003) and exercise duration (p = 0.04). Angina symptoms and exercise treadmill test results in this population had limited value for predicting anatomic restenosis 6 months after emergency angioplasty for acute myocardial infarction.

Prediction of early recurrent myocardial ischemia and coronary reocclusion after successful thrombolysis: a qualitative and quantitative angiographic study

To determine the association of qualitative and quantitative measurements of the myocardial infarct-related coronary narrowing with subsequent recurrent ischemia/reocclusion after successful thrombolysis, 47 patients treated with high-dose (150 mg) tissue plasminogen activator over 6 to 8 hours were studied in the setting of acute myocardial infarction. No patient underwent emergent coronary angioplasty. All patients had Thrombolysis in Myocardial Infarction (TIMI) grade 2 flow or higher at the baseline (90-minute) angiogram; 31 patients had a protocol 24-hour catheterization as well. Eighteen patients had recurrent ischemia/reocclusion whereas 29 had an uneventful hospital course. There was no significant difference in baseline clinical characteristics between the 2 groups. Twenty-five (86%) of those with an uneventful course had TIMI grade 3 flow at baseline angiogram compared with 56% of patients with recurrent events. No significant difference in angiographic morphologic characteristics was found between the 2 groups at baseline catheterization. At 24 hours, however, none of the patients who subsequently had recurrent events had a concentric narrowing, while 13 (58%) of them had a complex morphology. In contrast, quantitative parameters of minimal lumen diameter, percent area stenosis and percent diameter stenosis at baseline and 24 hours were not significantly different between those who did and did not have recurrent ischemia/reocclusion. These findings suggest that the degree and quality of coronary flow at baseline catheterization are more important determinants of sustained patency and event-free hospitalization than are quantitative dimensions or coronary morphology. In addition, narrowings that fail to become concentric within the first 24 hours are more likely to be associated with subsequent ischemia or reocclusion during the early periinfarct period.

Accuracy of digital angiography for quantitation of normal coronary luminal segments in excised, perfused hearts

The accuracy of coronary artery diameter determination by digital angiography was assessed by imaging 39 coronary segments of excised dog and human hearts and comparing these segments with pathologic sections 0.76 to 3.31 mm in luminal diameter. Digital images were obtained postmortem both during contrast injection using a fixed-pressure coronary perfusion system and after fixation when the coronary size was maintained by injection of a barium-gelatin casting mixture. Digital data were analyzed with commercially available, automated edge-detection software using a coronary catheter as the calibration standard. Coronary diameter measured during contrast injection was not significantly different from that measured after casting and fixation. Digital data from both methods correlated well with diameters from pathologic sections (injected, r = 0.85; fixed, r = 0.91). Linear regression parameters comparing pathologic diameters with the contrast injection method were slope = 0.82, intercept = 0.42 mm, and standard error of the estimate = 0.27 mm. Parameters for the comparison of pathology with casted coronary data were slope = 0.95, intercept = 0.16 mm, and standard error of the estimate = 0.23 mm. Intra- and interobserver variability were 3% (0.05 mm) and 4% (0.07 mm), respectively. These data indicate that when a coronary catheter as a calibration standard is used, coronary artery dimensions can be accurately measured by automated digital angiography techniques.

The Risk for Systemic Embolization Associated with Percutaneous Balloon Valvuloplasty in Adults: A Prospective Comprehensive Evaluation

STUDY OBJECTIVE To prospectively investigate the evidence for embolic phenomena associated with percutaneous mitral and aortic valvuloplasty. DESIGN Prospective, consecutive case series before and after balloon valvuloplasty. SETTING Referral center hospital and cardiac catheterization laboratory. PATIENTS Consecutive sample of 32 patients having balloon valvuloplasty for critical symptomatic stenosis of the mitral or aortic valve. Twenty-six patients had aortic stenosis; 6 had mitral stenosis. INTERVENTION Computed tomography of the head, funduscopy, and electrocardiography were done in all patients before and after valvuloplasty. Cardiac isoenzymes were measured serially in 19 patients. MEASUREMENTS AND MAIN RESULTS Previous cerebral infarction was seen in nine patients, with three showing a new abnormality after aortic valvuloplasty. In one of these patients a funduscopic hemorrhage was detected by photography. Total creatinine kinase and MB fraction were elevated in 1 of 19 patients. Serial electrocardiograms were unchanged in all patients. CONCLUSIONS The incidence of cerebral neurologic events and myocardial injury are acceptably low after balloon valvuloplasty of calcific aortic and mitral stenosis. Both episodes of symptomatic cerebral infarction occurred in patients with apparent bicuspid aortic valvular stenosis, suggesting that calcific bicuspid aortic stenosis may be associated with more neurologic events after aortic valvuloplasty.

Comparison of coronary stenosis quantitation results from on-line digital and digitized cine film images

To examine the effects of digital image acquisition mode and subtraction techniques on the results of coronary stenosis quantitation, 100 discrete lesions from 45 patients undergoing routine diagnostic angiography were analyzed in each of 3 image types: direct on-line digital, electrocardiogram-gated digital subtraction and digitized cine film images. For the geometric measurements (minimal lumen diameter and percent diameter stenosis) correlation coefficients for 2-way comparisons among the image types ranged from 0.90 to 0.96. Linear regression slopes ranged from 0.93 to 1.00, with intercepts from 0.03 to 0.07 mm for minimal diameter and -0.5 to 4.4% for percent diameter stenosis. For the videodensitometric percent area stenosis data, the correlation coefficients ranged from 0.80 to 0.89, with linear regression slopes from 0.84 to 0.89 and intercepts from 8.3 to 12.8%. Thus, the results of quantitative geometric measurements of coronary stenosis severity were not strongly affected by image acquisition mode (on-line versus cine film digitization) or by electrocardiogram-gated digital subtraction, while densitometric data correlated less well when on-line digital and digitized cine film acquisition methodology were compared.

Case Report: Rate-Related Left Bundle Branch Block with Chest Pain and Normal Coronary Arteriograms Treated by Exercise Training

A clinical observation of chest pain associated with the onset of rate-related left bundle branch block has been described in patients with normal coronary arteriograms. The authors used standard cardiac rehabilitation techniques for exercise training in a 47-year-old woman with these manifestations. Serial treadmill tests revealed that during the course of 3 months of exercise training, the heart rate at onset of LBBB gradually rose from 133 to 175 beats per minute, and she no longer developed symptoms during her routine daily activities or exercises. Exercise training was a successful nonpharmacologic strategy that delayed the onset of rate-related LBBB and chest pain in this patient and avoided the need for beta blocker therapy.

Echocardiographic guidance of cardiac catheterization for atrial septal defect in pregnancy

Abstract Cardiac disease is the most important cause of non-obstetrical maternal death. 1 Atrial septal defect (ASD), which has a 2:1 female predominance, is the most common congenital heart disease during pregnancy. 1 Echocardiographically guided cardiac catheterization may be an option in patients in whom definitive hemodynamic data are needed for decision making. 224