Balloon Dilation Procedures Research Articles

Intravascular ultrasound imaging: a new method for guiding interventional vascular procedures.

A method to assess the degree to which an atheroma plaque has been disrupted by percutaneous interventional methods could be of considerable benefit. An intravascular ultrasound catheter could provide quantitative information about the distribution and quality of the atheroma prior to and following a balloon dilatation, laser, or atherectomy procedure. Additionally, the ultrasound transducer could be configured within an angioplasty balloon to visualize the arterial wall in cross section during the dilatation. Visualization of the atheroma and arterial wall also might be of benefit to help characterize the type of tissue within the plaque, which may potentially help suggest which of several alternative therapies may be most effective. The intravascular imaging catheter would provide a feasible method of identifying normal and diseased arterial wall structures during diagnostic and interventional angiographic procedures. This distinction is critical during laser therapy of eccentric plaques to prevent exposure of the uninvolved wall (Fig. 7). These high quality ultrasound images may allow quantitative assessment of the extent of atheromatous involvement of artery walls as well as the character of the atheroma tissue. Such an approach, performed percutaneously in the catheterization lab, could represent a fundamental departure from traditional angiographic methods for assessing the severity of coronary, carotid, or peripheral arterial disease.

Pathology of Transluminal Balloon Angioplasty Used in the Treatment of Coronary Heart Disease

The author provides insight into what happens to arteries or saphenous vein bypass grafts with angioplasty. The morphologic and histologic changes in coronary arteries and saphenous vein bypass grafts subjected to balloon dilation procedures are described. Mechanisms of action, causes of restenosis, and effects of adjacent nondilated vessels are discussed, as well as why some interventional procedures work, others do not, and some have a promising future.

Further observations on the effect of balloon size on the short term and intermediate term results of balloon dilatation of the pulmonary valve.

The relation between the size of the balloon used for dilatation of the pulmonary valve and the extent of relief of pulmonary stenosis both immediately after and at intermediate term follow up was studied. Sixty four balloon dilatation procedures in 56 patients were divided into group 1-12 in which the ratio of the diameter of the balloon to that of the pulmonary annulus was less than or equal to 1.0--and group 2-52 in which the ratio was greater than 1.0. Both groups had similar mean (SD) pressure drops across the pulmonary valve before dilatation. Immediately after dilatation there was a significant reduction in the pulmonary valve gradient in both group 1 (84.3 (39.2) v 43.6 (26.8) mm Hg) and group 2 (92.8 (42.1) v 22.4 (13.6)mm Hg). On intermediate term follow up (6-34 months), residual pulmonary valve gradients were significantly lower in group 2 (20.8 (18.5)mm Hg) than in group 1 (75.0 (49.4) mm Hg), suggesting that restenosis was more common after dilatation with small balloons. These data suggest that although the immediate results with either small or large balloons are good, balloons that are larger than the pulmonary valve annulus produce more sustained relief of pulmonary stenosis. Further analysis within the group treated with larger balloons showed that the subgroup with a balloon/annulus ratio of 1.01-1.2 had more recurrences of stenosis (need for repeat balloon dilatation and larger number of patients with residual pulmonary valve gradients greater than 30 mm Hg) than subgroups with balloon/annulus ratios for diameters of 1.21-1.41, greater than 1.41, and greater than 1.5, in which there were no recurrences. Balloons that were > 1.5 times the size of the pulmonary valve annulus had no additional advantage over the other subgroups, namely, 1.21-- 1.4 and > 1.41. These results and reports of damage to the right ventricular outflow tract by oversized (> 1.5) balloons indicate that balloons that give a balloon/annulus ratio 1.2 -- 1.5 are the best for dilatation of the pulmonary valve.

Argon Laser-Assisted Peripheral Angioplasty

Pioneered several years ago by cardiologists and interventional radiologists, laser-assisted angioplasty for the ablation of occlusive atherosclerotic lesions in the peripheral and coronary circulations is now entering the domain of the vas cular surgeon, who has the ability to progress beyond the limitations of the percutaneous approach. In the initial 38 patients undergoing 51 lower extremity laser angioplasty/ balloon dilatation procedures for peripheral vascular occlusive disease, pedal pulses were restored in 32 (63%) limbs. The tandem procedure failed in 16 (31%); however, when improvement was assessed objectively by postoperative ankle/arm index evaluation, a positive outcome was achieved in 72 % of the patients. Three (6%) patients required femoral-popliteal bypass after balloon- related arterial dissection was identified. Although laser angioplasty can successfully open occluded arteries, new in traoperative angiographic equipment compatible with laser angioplasty and a variety of incrementally sized laser probes will facilitate refinement of the tech nology and enhance its application.

Thrombolytic therapy for femoral artery thrombosis after pediatric cardiac catheterization

Femoral artery thrombosis remains a well-known complication after cardiac catheterization. A study was undertaken to assess the efficacy of thrombolytic therapy for this complication. A total of 526 consecutive infants and children were prospectively evaluated after cardiac catheterization, and the medical charts of 42 patients who required femoral artery thrombectomy between 1975 and 1985 were reviewed. In the prospective study, patients were given a bolus injection of heparin, 150 U/kg, at the time the artery was entered. Patients with persistently absent or diminished pulse 2 hours after catheterization received a second bolus injection of 50 U/kg followed by an infusion of 20 U/kg/hr heparin for a maximum of 48 hours. If the affected leg pulse was absent or reduced and the systolic Doppler blood pressure was less than two thirds that of the unaffected leg, thrombolytic therapy was begun. In the 42 patients with surgical thrombectomy, there were no serious complications of surgery. Forty-five of the 526 patients (8.6%) had a decreased or absent pulse after catheterization. Of these 45 patients, 32 (71.1%) improved with systemic heparinization only. Thirteen patients (28.9%) had a persistently absent pedal pulse suggesting femoral artery thrombosis, despite continuous heparinization. Eleven patients were successfully treated with thrombolytic therapy and two required surgical thrombectomy. Intraarterial balloon dilatation procedures were performed in 8 of these 13 patients. Prothrombin time was prolonged (11.5 ± 1.06 to 52.3 ± 40.4 seconds; p < 0.025) and fibrinogen levels were significantly reduced (2.25 ± 0.79 to 1.52 ± 0.52 gm/dl; p < 0.01) during therapy. There were no serious complications, although four patients bled from the groin entry site. During follow-up (mean 2.7 months) in 8 of 11 patients, persistence of pedal pulses was noted in all. Systemic thrombolytic therapy can be used effectively in management of complications of femoral artery thrombosis after cardiac catheterization without serious complications; it compares well with surgical results. Initiation of therapy requires careful observation and hematologic monitoring during administration.

Pathology of transluminal balloon angioplasty used in the treatment of coronary heart disease

The author provides insight into what happens to arteries or saphenous vein bypass grafts with angioplasty. The morphologic and histologic changes in coronary arteries and saphenous vein bypass grafts subjected to balloon dilation procedures are described. Mechanisms of action, causes of restenosis, and effects of adjacent nondilated vessels are discussed, as well as why some interventional procedures work, others donot, and some have a promising future

Transient prolongation of the QTc interval after balloon valvuloplasty and angioplasty in children

QTc-interval changes were evaluated in 39 children who had undergone balloon dilation procedures. In 30 children who had undergone balloon pulmonary valvuloplasty (BPV), QTc intervals were measured on standard electrocardiograms recorded before and 16 to 24 hours after the procedure and at follow-up during the next 1 to 15 months (mean 7). The QTc interval increased from 0.380 ± 0.027 second before BPV to 0.429 ± 0.027 second after BPV (p < 0.002) and returned to 0.377 ± 0.026 second at follow-up. To determine when during the catheterization-dilation procedure the QTc interval increased, QTc intervals were measured on monitor electrocardiograms recorded during cardiac catheterization. The baseline QTc was 0.382 ± 0.041 second, was unchanged after angiography and increased to 0.427 ± 0.043 second after BPV (p < 0.002). A similar prolongation occurred in 3 of 4 children who had undergone balloon aortic valvuloplasty and in 4 of 5 who had undergone coarctation angioplasty. In control children, who had undergone catheterization without dilation, QTc was unchanged. Thus, transient increases in QTc interval occur after semilunar valvuloplasty and coarctation angioplasty. These dilation procedures are a cause of QTc prolongation; however, the mechanism is unknown. It is possible that the sudden unilateral increase in afterload affects the myocardium or myocardial sympathetic receptors. Because QTc prolongation may predispose children to the R-on-T phenomenon, postprocedure monitoring appears to be warranted.

Fibrinolytic therapy for femoral arterial thrombosis after cardiac catheterization in infants and children

The charts of 79 patients who required femoral arterial (FA) thrombectomy after cardiac catheterization were reviewed. Fifteen patients (19%) had poor pulses after thrombectomy and 2 had an extremity amputated. One thousand consecutive patients undergoing cardiac catheterization were also studied to prospectively determine the safety and efficacy of systemic fibrinolytic therapy for treatment of FA thrombosis. Among these, 771 patients underwent retrograde arterial catheterization, including 31 patients with left-sided obstructive lesions who had undergone transarterial balloon dilation procedures with large catheters. All patients were given heparin at the time of arterial cannulation. Patients who had a pulseless extremity 4 hours after catheterization continued to receive heparin therapy for 24 to 48 hours. If the extremity continued to have no palpable pulse and the systolic blood pressure was less than 50% of that in the contralateral leg, intravenous streptokinase infusion was begun. The overall incidence of FA thrombosis was 3.6% (28 of 771), including 39% (12 of 31) of all patients undergoing transarterial balloon dilation procedures; 97% (27 of 28) of patients weighed less than 14 kg and the majority weighed less than 10 kg. After an average treatment period of 33 hours, 16 patients continued to have a pulseless extremity and were treated with streptokinase for an average duration of 13 hours. Normal pulses and systolic blood pressure returned in 14 (88%) and were nearly normal in 1 other patient (6%). The incidence of bleeding at the arterial puncture site was 25% and was highest in the patients who had a transarterial balloon dilation procedure. No serious complications occurred.