Ivar Enge

Amipaque: A New Contrast Medium in Coronary Angiography: Report of a Double-Blind Study in Man

Isopaque Coronar and Amipaque (metrizamide) were evaluated in a comparative double-blind study of 30 patients with heart disease undergoing selective coronary angiography. Amipaque alone was also used for 9 additional patients undergoing left ventriculography, aortic root injection, and selective coronary angiography. Amipaque resulted in significantly less of a decrease in diastolic pressure and heart rate, reduced chest pain and heat sensation, and longer coronary contrast transit time. Electrorocardiographic parameters and image quality were equivalent with the 2 agents. No pathological changes were noted in the 9 patients undergoing complete angiocardiographic study.

Induced Thrombosis in the Pig Inferior Vena Cava: A Model of Deep Venous Thrombosis

PURPOSE To establish a new animal model of deep venous thrombosis. MATERIALS AND METHODS Fifteen young pigs underwent temporary interruption of the inferior vena cava (IVC) below the entry of the right renal vein by means of either a silicone band (surgical technique, n = 6) or an intraluminal balloon catheter (endovascular technique, n = 9), followed by injection of absolute ethanol. Lumbar veins within 3 cm below the obstruction were ligated or occluded interventionally. The iatrogenic caval obstruction was relieved after 2 days. RESULTS Procedure-related mortality was 33% (n = 2) and 11% (n = 1) for the surgical and endovascular groups, respectively. An adherent, occlusive thrombus was found in all four of the remaining surgically treated animals and in six of eight animals treated percutaneously. The IVC remained patent in two animals in whom balloon migration occurred. Severe caval stenosis invariably occurred after surgical banding. CONCLUSION IVC thrombi suitable for the study of various recanalization therapies can be reliably created with this pig model.

Long-term results after aortic valve replacement with four different prostheses

Abstract The long-term results after implantation of isolated aortic ball and disc prostheses were studied. The Starr-Edwards ball valve type 1200 was first used in 80 patients, thereafter type 2300 was used in 173, later the Bjork-Shiley and the Lillehei-Kaster disc valves were implanted in 99 and 97 patients according to randomization. The surviving patients with the oldest ball valve were examined after 4.7 and 6.7 years on an average, the others after approximately 2.5 and 4.5 years. The early mortality rate was 15%, and did not differ between the four groups. Even the late mortality rate was quite similar in the patient groups, the five-year survival rate being 65% in patients with ball valves and 68% in those with disc valves, as estimated with the actuarial method. The average reduction of heart size was moderate and quite similar in the four groups, most pronounced in patients with isolated aortic valve involvement. The reduction was greater in patients who received larger rather than smaller valves of all types. Aortic valve replacement resulted in a considerable clinical improvement in patients with all valve types; it corresponded largely to one functional group according to the NYHA classification. The heart size reduction and functional improvement was most moderate in patients with smaller ball valves, which could be anticipated from higher peak systolic gradients than across the other valves used. No significant differences appeared between patients with the larger valves of the four types. The initial improvement, as recorded either by reduction of heart size or increase in functional capacity, had reached its maximum at the first follow-up examination in most patients. The preoperative myocardial function appeared to be the limiting factor which determined what late results could be obtained regardless of the type of valve implanted. The results therefore indicate that more can be achieved by earlier valve replacement than by improving the prostheses.

In vitro evaluation of a new temporary venous filter: the Spring filter.

PurposeTo evaluate in vitro the functional efficacy of a new variable-sized, temporary venous filter, the Spring filter (SF).MethodsThe SF was tested in a flow phantom, using flexible, thin-walled polyethylene tubes 12, 14, and 16 mm in diameter to simulate veins. Clots of three sizes were used: 6 × 10 mm, 6 × 20 mm, 9 × 20 mm. Filter deployment was performed, ensuring that its functional diameter after placement was a predetermined multiple of the radius ‘r’ of the tube: 3.0r, 2.8r, 2.6r, 2.4r. The terminal coil was visually examined for changes in configuration. Clot retention by the filter for a period of 3 min was recorded as a success. The baseline intraluminal pressure and the maximum pressure reached after clot introduction were recorded. The trapping ability was calculated from the results for 10 clots. The effect of the following parameters on filter function were studied: size of embolus, caliber of simulated vein, and functional diameter of filter.ResultsThe filter configuration was stable. Not a single instance of axial tilting occurred on deployment. Functional diameter was the major determinant of filter function. One hundred percent of clots were trapped irrespective of clot size and tube caliber when the functional diameter was 3.0r. Only 73% (95% confidence interval (CI): 57%–88%) and 77% (95% CI: 61%–92%) of small emboli were held up by the filter when the functional diameters were 2.6r and 2.4r, respectively (p = 0.0001). A significant reduction in clot trapping was encountered even with medium clots when the functional diameter was 2.4r (p = 0.02).ConclusionAgainst the background of available data on retrievable vena caval filters, the current model of SF warrants further investigation.

In vitro function of an adjustable temporary venous spring filter: comparison with the temporary RF02 filter and the permanent Greenfield vena cava filter.

RATIONALE AND OBJECTIVES The authors compared in vitro function of a temporary venous spring filter with that of a temporary RF02 filter and a permanent Greenfield filter. MATERIALS AND METHODS All three types of filters were placed in thin polyethylene tubes (diameters, 10.0-18.0 mm). Physiologic saline was substituted for flowing blood, and blood clots of three sizes (6 x 10 mm, 6 x 20 mm, 9 x 20 mm) were funneled to the filters. Clot-trapping ability of each filter and elevation of intraluminal pressure after clot trapping were assessed for each tube size. RESULTS No statistically significant elevation in intraluminal pressure was detected immediately after placement of any filter. The clot-trapping ability of the spring filter and of Greenfield filter were slightly lower than that of the RF02 filter, but the differences were not statistically significant. After filters had trapped large clots, a high pressure gradient was detected in the 10.0-mm tube for all filters. The spring filter was associated with a higher pressure than the other filters in the 12.0-mm tube (P < .05). CONCLUSION In vitro function of the spring filter was satisfactory in comparison with that of the RF02 filter and the Greenfield filter. For efficient filtering in the inferior vena cava, development of a larger version of the filter may be necessary.

Adjustable temporary venous spring filter: in vitro assessment.

RATIONALE AND OBJECTIVES The authors performed an in vitro study to evaluate a temporary venous spring filter that can extend vessels of a wide range of diameters to a slit-shaped canal. MATERIALS AND METHODS Filters were placed in thin polyethylene tubes or in porcine inferior vena cava specimens (diameter, 10.0-16.0 mm). Physiologic saline was substituted for blood flow, and blood clots of three sizes (6 x 10, 6 x 20, and 9 x 20 mm) were funneled to the filter. Clot-trapping ability was assessed by the degree of luminal extension. RESULTS When the luminal extension was increased from 2.6r to 2.8r (where r is the original radius of the vein models), clot-trapping ability increased significantly (61.1%-87.5% in polyethylene tubes and 15.8%-77.5% in venous specimens, P < .001). When the luminal extension was increased to 3.0r, more than 90% of the clots were trapped in all tubes. After trapping the small, medium, and large clots, mean intraluminal pressure elevation was 1.0, 1.0, and 17.0 cm of saline, respectively. CONCLUSION Despite its simple design, the spring filter proved to be an efficient filtering device.

Left coronary artery contrast transit time

With our method for selective left coronary arteriography it is possible to determine the time interval between the start of the contrast injection into the artery and the appearance of the contrast in the coronary sinus. This time-interval, coronary contrast transit time (CCTT), has been determined in patients with or without obstructing coronary artery disease. The average CCTT was about four seconds with some individual variations. The CCTT tended to decrease with advancing age. There was no significant difference between the CCTT in patients with normal angiograms compared to the CCTT in patients with coronary stenoses or occlusions. In the latter patients, there was no correlation between the degree of narrowing on the angiograms and the time-measurements. Alternative explanations for these findings are discussed.

Clinical and hemodynamic results after combined aortic and mitral valve replacement with the Lillehei-Kaster pivoting disc valve.

Combined mitral and aortic valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis was performed in 23 patients. Hospital mortality rate was 8.3 per cent. Detailed postoperative clinical and hemodynamic studies were performed after a mean follow-up period of 24.4 months. Replacement of both valves had resulted in a marked symptomatic and hemodynamic improvement with a normal or nearly normal resting value of cardiac output, pulmonary arterial pressure, and pulmonary vascular resistance while left ventricular end-diastolic pressure (LVEDP) had increased significantly. The rise in left ventricular end-diastolic pressure most probably might be related to the simultaneous rise in cardiac output (Starling mechanism), reflecting the severity and irreversibility of the underlying myocardial disease. Most patients also had systolic gradient across the aortic prosthesis, as well as diastolic gradient across the mitral prosthesis. The gradients across the mitral prosthesis were approximately the same as seen after single valve replacement, while the pressure gradients across the aortic prosthesis were somewhat smaller than previously reported. Angiographic studies of the aortic valve movement indicated that the opening angle of the disc was approximately 60 degrees, and thus less than according to the valve specifications.

Metrizoic Acid (Isopaque Coronar) Used in Man for Cardiac Angiography

Isopaque Coronar, a radiopaque agent, was given (10,000 injections) to 2,028 patients during angiocardiographic studies done over a three-year period. With two exceptions, all complications occurred during right coronary artery injection. Seven cases of ventricular fibrilation, and 5 of marked bradycardia/asystole, were associated with injection of the medium. Isopaque Coronar is well tolerated by patients during cardiac examinations. Factors which may help to explain the low complication rate are discussed.

Placement of a spring filter during interventional treatment of deep venous thrombosis to reduce the risk of pulmonary embolism.

Purpose: To assess the efficacy of the Spring filter during interventional treatment of deep venous thrombosis in vivo. Material and Methods: A model of inferior vena cava thrombosis was used. Part I: the thrombus was treated by the pulse-spray technique (PT) (urokinase 250,000 IU; n=7) or a rotatory basket catheter, Thrombolizer (MT) (activated with compressed air at 7 atm; n=5). Part II: Following placement of a Spring filter, the animal underwent PT (n=5) or MT (n=5). Based on the results of part I, the treatment protocol was modified (PT, urokinase 500,000 IU; MT, compressed air at 8 atm). Embolus volumes trapped by the filter and found in the lungs were calculated and the filtering efficacy quantified. Results: Part I: Pulmonary emboli (1 to 4 mm in diameter) were observed in 3 animals in the PT group and 1 animal in the MT group, respectively. Median reduction in thrombus volume was 21% and 4% by PT and MT, respectively. Part II: In the PT group, 58% and 100% of the total embolus load was trapped in 2 animals, while the filter failed to trap emboli (1 to 1.5 mm in diameter) in 1 animal. In the remaining 2 animals, no embolus was found trapped by the filter or in the lungs. In the MT group, 55–97% (median 83%) of the embolus load was trapped. Emboli found in the lungs did not exceed 4 mm in diameter. Conclusion: Preceding interventional treatment of venous thrombosis with placement of the Spring filter reduced the embolic burden on the lungs.