Effects of monoionic and nonionic radiographic contrast media on cutaneous microcirculation in patients with peripheral arterial occlusive disease

Temporary decrease in microvascular tissue saturation after transcatheter aortic valve implantation

BACKGROUND

Data on the effect of transcatheter aortic valve implantation (TAVI) on peripheral microcirculation are limited.

OBJECTIVE

The aim of this study is to evaluate peripheral microvascular tissue saturation (StO2) before and after TAVI in relation to central and peripheral hemodynamics, cardiac and renal function.

METHODS

In this single-center prospective study, patients with severe aortic stenosis (sAS) scheduled for TAVI or cardiac catheterization (control) were assessed before and up to five days after the procedure. Cardiac function including cardiac output (CO) was assessed by echocardiography. Brachial (bBP) and central blood pressure (cBP), ankle brachial index (ABI), and parameters of arterial stiffness, including augmentation pressure (AP) and augmentation index adjusted for heart rate (AIx@HR75) were measured to assess hemodynamic changes. StO2 was measured in all extremities using a near-infrared spectroscopy (NIRS) camera. Renal function was measured by creatinine levels.

RESULTS

26 patients underwent TAVI and 11 patients served as control. Cardiac output was significantly increased, whereas hemodynamic parameters and peripheral StO2 were significantly decreased after TAVI. At follow-up, StO2 returned to baseline values. Changes in StO2 were negatively related to creatinine levels.

CONCLUSION

Transcatheter aortic valve implantation causes a temporary decrease in microvascular tissue saturation that is associated with renal function.

Improvement of microcirculation after percutaneous transluminal angioplasty in the lower limb with prostaglandin E1

OBJECTIVE

The aim of the study was to investigate prospectively the microcirculation after angioplasty and its improvement with additional Prostaglandin E1 (PGE1) therapy assessed by transcutaneous pressure of oxygen.

PATIENTS AND METHODS

45 patients with intermittent claudication eligible for angioplasty were enrolled in a prospective randomised controlled clinical trial. Patients received either intra-arterial bolus of 40 microg PGE1 in addition to angioplasty or a 40 microg PGE1 intravenous infusion. Control group received no trial medication. Additional 15 patients undergoing intra-arterial angiography were also investigated. tcpO(2) values were recorded distal to the PTA region before, during the intervention, 24h, 2 and 4 weeks after intervention. Clinical endpoint was the change of tcpO(2) values 4 weeks after intervention.

RESULTS

During the 4 week follow-up tcpO(2) values decreased in patients treated with angioplasty. At the same time tcpO(2) increased significantly in those patients additionally treated with intra-arterial PGE1 bolus injection as well as with intravenous PGE1 infusion.

CONCLUSIONS

Impaired microcirculation after angioplasty can be improved with additional intravenous as well as intra-arterial PGE1 administration.

Transcutaneous oximetry compared to ankle-brachial-index measurement in the evaluation of percutaneous transluminal angioplasty

OBJECTIVE

To investigate transcutaneous oximetry as parameter of the microcirculation is correlated to ankle-brachial-index as parameter of the macrocirculation after peripheral angioplasty procedures.

DESIGN

Prospective study.

MATERIALS AND METHODS

60 patients suffering from intermittent claudication were scheduled for angioplasty treatment. 45 patients were considered as eligible for angioplasty after angiographic evaluation, 15 patients underwent angiography only. Transcutaneous oximetry measurements were performed before the procedure, at the end of intervention, 24h as well as 2 and 4 weeks after percutaneous transluminal angioplasty. Ankle-brachial-indices were obtained before intervention, 24h as well as 2 and 4 weeks later.

RESULTS

Ankle-brachial-indices increased significantly at 24h after angioplasty in patients being treated with angioplasty. Transcutaneous oximetry values dropped significantly at the end of the procedure and returned close to the baseline levels at 2 and 4 weeks after angioplasty. Ankle-brachial-indices and transcutaneous oximetry were positively correlated before (r=0.3833, p=0.009) as well as 4 weeks after angioplasty (r=0.4596, p=0.001). Immediately after radiological interventions, ankle-brachial-indices and transcutaneous oximetry are not positively correlated. In patients undergoing angiography only, transcutaneous oximetry levels drop significantly immediately after angiography and remain at decreased levels even at 4 weeks after intervention.

CONCLUSION

Transcutaneous oximetry as parameter of the microcirculation is positively correlated with ankle-brachial-index as parameter of the macrocirculation before and at 4 weeks after angioplasty. Intraarterial angiography leads to a sudden decrease in skin microcirculation without affecting macrocirculation. As indicated by a lack of recovery in transcutaneous oximetry levels after 4 weeks, angiography alone results in a prolonged impaired microcirculation which may reflect endothelial dysfunction caused by contrast material. The recovery of transcutaneous oximetry levels following angioplasty is counterbalanced by the adverse effects of the contrast material. Ankle-brachial-indices remains the most favourable parameter in evaluating the success of angioplasty procedures while transcutaneous oximetry serves as an indirect method in assessing endothelial dysfunction caused by contrast material.

Influence of percutaneous transluminal angioplasty on transcutaneous oxygen pressure in patients with peripheral arterial occlusive disease

PURPOSE

To determine in a prospective controlled trial the effect of percutaneous transluminal angioplasty (PTA) on skin oxygen supply and microcirculation as measured by means of transcutaneous oxygen pressure in patients with disabling lower-limb ischemia compared with that in patients who underwent intraarterial angiography for the assessment of disabling lower-limb ischemia.

MATERIALS AND METHODS

Thirty-four patients (17 men, 17 women; mean age, 68.6 years +/- 9.8 [SD]) with peripheral arterial occlusive disease (PAOD) (claudication, n = 15; critical ischemia, n = 19) underwent transcutaneous oxygen pressure measurement at the dorsum of the foot 1 day before PTA, during PTA, 1 day after PTA, and 6 weeks after PTA. Measurements were obtained with the patient in the supine and erect sitting positions, as well as after exercise. Thirty-one patients (21 men, 10 women; mean age, 68.5 years +/- 9.3) with symptomatic PAOD who were undergoing intraarterial angiography served as the control group.

RESULTS

Mean pressure before PTA was 31.6 mm Hg +/- 24 in the supine position, 50.8 mm Hg +/- 22 in the sitting position, and 22.2 mm Hg +/- 23 after exercise. Immediately after PTA, a significant increase to 34 mm Hg +/- 20 in the supine position was noted (P <.05). One day after PTA, pressure was 37.3 mm Hg +/- 20 for the supine position and 52 mm Hg +/- 20 for the sitting position. Six weeks after treatment, a further significant increase to 43.9 mm Hg +/- 19 in the supine position, 61 mm Hg +/- 15 in the sitting position, and 44.7 mm Hg +/- 24 after exercise was noted (P <.05). In the control group, a significant pressure decrease immediately after and 1 day after angiography was noted (P <.05). Measurements returned to baseline at 6 weeks follow-up.

CONCLUSION

PTA has a positive effect on oxygen supply to the skin in patients with PAOD. Conversely, intraarterial angiography in patients with PAOD deteriorates skin microcirculation temporarily.

The haemodynamic effects of iodinated water soluble radiographic contrast media: a review

All classes of iodinated water-soluble radiographic contrast media (RCM) are vasoactive with the iso-osmolar dimers inducing the least changes in the vascular tone. The mechanisms responsible for RCM-induced changes in the vascular tone are not fully understood and could be multifactorial. A direct effect on the vascular smooth muscle cells causing alterations in the ion exchanges across the cell membrane is thought to be an important factor in RCM-induced vasodilatation. The release of the endogenous vasoactive mediators adenosine and endothelin may also play a crucial role in the haemodynamic effects of RCM particularly in the kidney. In addition, the effects of RCM on blood rheology can cause a reduction in the blood flow in the microcirculation. The purpose of this review is to discuss the pathophysiology of the haemodynamic effects of RCM and to offer some insight into the biology of the endothelium and vascular smooth muscle cells as well as the pharmacology of the important vasoactive mediators endothelin and adenosine.