Vasomotor effects of iodinated contrast media: just side effects?

Risk of Major Cardiovascular Disease after Exposure to Contrast Media: A Nationwide Population-Based Cohort Study on Dialysis Patients

Contrast associated kidney injury is caused by side effects of iodinated contrast media (ICM), including inflammation. Chronic inflammation among dialysis patient contributes to atherosclerosis, which leads to simultaneous conditions of the kidney, brain, and vasculature. Data to investigate the pathologic effects of ICM on cardiovascular complications in dialysis patients are lacking. Dialysis patients who had been exposed to ICM from computed tomography (ICM-CT) were allocated as the ICM-CT cohort (N = 3751), whereas dialysis patients without ICM exposure were randomly allocated as the non-ICM cohort (N = 17,196). Furthermore, 540 pairs were selected for analyses through propensity score-matching in terms of age, sex, comorbidities, dialysis vintage, and index date. During a median follow-up of 10.3 years, ICM-CT cohort had significantly higher risks in the following, compared with non-ICM cohort: all-cause mortality (adjusted hazard ratio [aHR], 1.36; 95% confidence interval [CI], 1.26-1.47), cardiovascular events (aHR,1.67; 95% CI, 1.39-2.01), acute coronary syndrome (adjusted HR: 2.92; 95% CI, 1.72-4.94), sudden cardiac arrest (aHR, 1.69; 95% CI, 0.90-3.18), heart failure (aHR, 1.71; 95% CI,1.28-2.27), and stroke (aHR, 1.84; 95% CI,1.45-2.35). The proinflammatory ICM is significantly associated with an increased risk of major cardiovascular events in patients on dialysis.

Gender Specific Coronary Artery Diameters in CT Coronary Angiogram: A Comparative Study in Female and Male Population

Objectives:

Women show significant in-hospital morbidity and mortality with greater extent of symptoms, poorer post-revascularization outcome with increased restenosis and repeat revascularization after angioplasty, than men. Smaller sized coronary arteries in females can be attributable for this differential outcome, which is also similar in case of Indians, compared to Caucasians. Our aim is to assess the gender-specific difference in coronary arteries using noninvasive Multidetector Computed-Tomography Coronary-Angiogram(CT-CAG) and comparing the same with other racial database.

Materials and Methods:

With Ethics committee approval, present retrospective comparative study conducted in 128CT-CAG scans in 18-45years aged 100 women and 89 men with no atherosclerotic burden excluding pathological coronaries and high calcium score>100. Diameter measurements of proximal (≤10mm) segments of right coronary artery(RCA), left main coronary artery(LMCA), left anterior descending(LAD) and circumflex(LCx) arteries were taken, averaged and compared using 2-sample z-test. Considering the obtained mean diameters of total sample as South-Indian dataset which is then compared with Caucasians dataset taken from previous study.

Results:

Women showed smaller coronary artery diameters compared to men in all the arteries, with greater gender-specific age-adjusted difference in LMCA, followed by LAD, RCA and least in LCX. South-Indians showed statistically significant smaller diameters of all the coronary arteries compared to Caucasians.

Conclusion:

Gender-specific difference among the coronary arteries does exist, with females having smaller dimensions; South-Indians also show smaller diameters. This warrants a clinician for gender-specific approaches during the interventions because of technical difficulties.

Migraine and Non-Migraine Headaches Following Diagnostic Catheter-Based Cerebral Angiography

BACKGROUND AND OBJECTIVE

No reliable estimates of headaches following catheter-based cerebral angiography are available. We performed an observational cohort study to ascertain the frequency and type of headaches following catheter-based cerebral angiography.

MATERIALS AND METHODS

Consecutive patients who underwent cerebral angiography through the transfemoral (or infrequently radial) route were included. Each patient underwent a brief neurological assessment after the procedure and more detailed assessment was performed if any patient reported occurrence of a headache. The headaches were classified as migraine if the diagnostic criteria specified by International Headache Society were met. The headache severity was classified using a visual numeric rating scale and time to reach pain free status for 2 consecutive hours was ascertained.

RESULTS

Migraine headaches occurred in 5 (3.1%, 95% confidence interval [CI] 1.0-7.2%) of 158 patients who underwent cerebral angiography. The median severity of migraine headaches was 10/10 and time to resolution of headaches was 120 minutes (range 60-360 minutes). Migraine headaches occurred in 4 (18.1%, 95% CI 5.2-40.3%) of 22 patients with a history of migraine and 4 (23.5%, 95% CI 6.8-50%) of 17 patients with regular migraine headaches (≥1 episodes per month). Headaches occurred in 6 (3.8%, 95% CI 1.8-8.0%) patients who did not meet the criteria for migraine headaches.

CONCLUSIONS

We provide occurrence rates of migraine headaches, an under-recognized adverse event, in patients undergoing catheter-based cerebral angiography.

Pattern of vascular remodeling of distal reference segment after recanalization of chronic total occlusion, long-term angiographic follow-up

Chronic total occlusion (CTO) is probably caused by thrombus and lipid-rich cholesterol esters that are replaced over time by collagen and calcium deposition. Experimental models showed endothelial cell necrosis in response to vessel ligation, whereas more recent models suggest that the endothelium might retain viability guiding the subsequent development of CTO, including CTO neo-revascularization, which occurs within the lumen and in various layers of the vessel wall, by the release of paracrine substances. It is uncertain whether after CTO recanalization the recovery of anterograde reverses endothelial dysfunction, thus promoting vasodilation and positive remodeling.

Limitations in learning: How treatment verifications fail and what to do about it?

PURPOSE

The purposes of this study were: to provide dialog on why classic incident learning systems have been insufficient for patient safety improvements, discuss failures in treatment verification, and to provide context to the reasons and lessons that can be learned from these failures.

METHODS AND MATERIALS

Historically, incident learning in brachytherapy is performed via database mining which might include reading of event reports and incidents followed by incorporating verification procedures to prevent similar incidents. A description of both classic event reporting databases and current incident learning and reporting systems is given. Real examples of treatment failures based on firsthand knowledge are presented to evaluate the effectiveness of verification. These failures will be described and analyzed by outlining potential pitfalls and problems based on firsthand knowledge.

RESULTS

Databases and incident learning systems can be limited in value and fail to provide enough detail for physicists seeking process improvement. Four examples of treatment verification failures experienced firsthand by experienced brachytherapy physicists are described. These include both underverification and oververification of various treatment processes.

CONCLUSIONS

Database mining is an insufficient method to affect substantial improvements in the practice of brachytherapy. New incident learning systems are still immature and being tested. Instead, a new method of shared learning and implementation of changes must be created.

Intracranial extravasation of contrast medium during diagnostic CT angiography in the initial evaluation of subarachnoid hemorrhage: report of 16 cases and review of the literature

INTRODUCTION

Three-dimensional CT angiography (3D-CTA) is increasingly used in the initial evaluation of subarachnoid hemorrhage (SAH). However, there is a risk of aneurysm re-rupture in the hyperacute phase. We sought to clarify the incidence of re-rupture and characterize the subgroup in which extravasation of contrast media was seen on 3D-CTA.

METHODS

We examined the records of 356 consecutive patients presenting to our institution with non-traumatic SAH between October 2003 and December 2011. After resuscitation, patients with poor grade SAH underwent CT then 3D-CTA while sedated, mechanically ventilated and with a target systolic blood pressure of 120 mmHg.

RESULTS

336 patients underwent 3D-CTA; 20 died without return of spontaneous circulation. Extravasated contrast medium was seen in 16 (4.8%), 15 (4.5%) at the initial evaluation. Their World Federation of Neurosurgical Societies Grade was V; one patient was resuscitated from cardiac arrest. The mean times from onset to arrival and to CTA were 43.7 minutes and 71.8 minutes, respectively. Ten patients (62.5%) had episodes suggestive of aneurysm re-rupture before 3D-CTA. Surgical clipping, evacuation of hematoma and wide decompressive craniectomy was completed in six patients and one underwent coil embolization. Two of 16 patients survived: one with moderate disability and one made a good recovery.

CONCLUSIONS

Contrast extravasation was detected by 3D-CTA in 4.5% of cases despite intensive resuscitation, suggesting that continuous or intermittent rebleeding may occur frequently in the hyperacute phase. The consequences of rebleeding are devastating; however, favorable results can be obtained with immediate aneurysm repair with decompression and intensive neurocritical care.

Transient impairment of vasomotion function after successful chronic total occlusion recanalization

OBJECTIVES

The aim of our study was to assess coronary vasomotion after successful revascularization of chronic total occlusion (CTO).

BACKGROUND

It is largely unknown whether the recovery of anterograde flow after CTO recanalization with drug-eluting stent implantation affects vascular function in distal coronary segments.

METHODS

One hundred consecutive CTOs successfully treated with drug-eluting stents underwent coronary diameter measurement after intracoronary nitroglycerin injection 5, 20, and 35 mm distal to the stented coronary segment using 3-dimensional quantitative coronary angiography. In a subgroup of 14 patients, coronary vasomotion was tested in distal segments: incremental atrial pacing for endothelium-dependent cases; and intracoronary nitroglycerin injection for endothelium-independent cases. In another subgroup of 13 patients, distal vessels were assessed by intracoronary ultrasounds.

RESULTS

Vessel diameters significantly increased at follow-up as compared to baseline values (2.0 ± 0.52 mm vs. 2.25 ± 0.50 mm, 1.76 ± 0.49 mm vs. 2.05 ± 0.58 mm, 1.54 ± 0.53 mm vs. 2.04 ± 0.58 mm, at each segment analyzed; p < 0.001). At baseline, distal segments failed to respond to both endothelium-dependent and -independent stimuli. At follow-up, atrial pacing induced vasoconstriction, whereas nitroglycerine administration resulted in significant vasodilation (p < 0.05). Intracoronary ultrasounds failed to show changes of the cross-sectional area of distal segments at follow-up angiography.

CONCLUSIONS

Recanalization of CTO is followed by a hibernation of vascular wall at distal coronary segments that fail to respond to endothelium-dependent and -independent stimuli. Distal vessel diameter increases over time in the absence of positive remodeling and in spite of persistent endothelial dysfunction. This severe impairment of vasomotor tone after CTO reopening suggests that intracoronary ultrasound assessment is of paramount importance for the selection of stent size.

Gender-related differences in coronary artery dimensions: a volumetric analysis

BACKGROUND

Women consistently have poorer revascularization outcomes and more coronary vascular complications compared to men. This has been attributed to smaller coronary arteries, though limited data exist to support this assumption.

HYPOTHESIS

By using volumetric data obtained from multidetector cardiovascular computed tomography (CCT), we sought to determine to what extent gender influences coronary artery dimensions and test the hypothesis that women would have smaller coronary dimensions even after normalizing for body surface area and cardiac mass.

METHODS

CCT examinations completed on a 64-slice scanner were identified from a university cardiovascular database. Data sets from 50 women and 44 men without coronary artery disease were selected for analysis. Cross-sectional areas of proximal and distal segments of the left anterior descending (LAD), circumflex (LCx), and right coronary artery (RCA) were measured, blinded to patient gender. Measurements were compared using 2-sample t tests and linear regression analysis techniques accounting for body surface area (BSA) and left ventricular (LV) mass.

RESULTS

Analysis of cross-sectional coronary artery areas, unadjusted for BSA and LV mass showed smaller coronary artery size in women compared to men in the proximal portion of both the LAD (P = .01) and RCA (P = .002), but no significant difference in the remaining coronary segments.

CONCLUSION

Gender significantly impacts proximal LAD and RCA size. Differences in coronary artery dimensions may explain some, but not all excess gender-related risk with coronary artery revascularization, underscoring the importance of considering multiple contributing factors.

Effects of iodinated contrast media on common carotid and brachial artery blood flow and wall shear stress

The aim of our study was to evaluate the effect of the intravenous contrast media iomeprol on wall shear stress, blood flow and vascular parameters in the common carotid and brachial artery. Thirty outpatients undergoing thoracic or abdominal spiral CT scans were studied. The internal diameter and flow velocity of the common carotid and brachial artery were evaluated by ultrasound, and blood viscosity was measured before and after low osmolality iomeprol (Iomeron 350) injection. The wall shear stress, blood flow and pulsatility index were calculated. To test the differences between groups, the Wilcoxon rank test and Mann Whitney U test were applied. Blood viscosity decreased slightly, but significantly after contrast media (4.6+/-0.7 vs. 4.5+/-0.7 mPa.s, P = 0.02). Contrarily, blood flow and wall shear stress did not change in the common carotid artery, but significantly decreased in the brachial artery (0.9+/-0.4 vs. 0.6+/-0.3 ml/s, P < 0.0001, and 41.5+/-13.9 vs. 35.3+/-11.0 dynes/cm2, P < 0.002, respectively), whereas the pulsatility index significantly increased in the brachial artery (5.0+/-3.3 vs. 7.5+/-5.3, P < 0.001). Iomeprol injection causes blood flow and wall shear stress reduction of the brachial artery; the rise in the pulsatility index suggests an increase in peripheral vascular resistance. Further investigation is needed to evaluate whether these modifications can be clinically relevant.