Left ventricular thrombosis and arterial embolism after thrombolysis in acute anterior myocardial infarction: predictors and effects of adjunctive antithrombotic therapy

The prevalence of left ventricular (LV) thrombosis and incidence of arterial embolism after acute anterior myocardial infarction (AAMI) treated with streptokinase 1.5 x 10(6) IU intravenously was studied in 136 patients enrolled consecutively in five cardiological centres. Adjunctive antithrombotic therapy was administered according to the routine of each centre. Thrombus formation was studied by two-dimensional echocardiography, and events of arterial embolism recorded. LV thrombosis was found in 37 (27.2%) of the patients. In a subgroup of 53 patients receiving post-thrombolytic therapy with acetylsalicylic acid only, a thrombus developed in 14 (26.4%). The thrombus prevalence among patients given high-dose heparin was significantly lower than among those receiving either low-dose heparin or no heparin (4/30 vs 33/106, P = 0.045). Logistic regression analysis suggested that severe LV wall motion abnormality (P < 0.001) and avoidance of treatment with high-dose heparin (P = 0.023) were independent predictors of LV thrombus formation. Only one patient (0.7%) suffered arterial embolism (ischaemic stroke). In conclusion, LV thrombosis is frequent after thrombolytic therapy for AAMI, and impaired LV wall motion represents an independent predisposing factor. Low-dose heparin and acetylsalicylic acid seem less effective for LV thrombus prophylaxis than high-dose heparin. The incidence of arterial embolism is low.

Adverse effect of warfarin in acute myocardial infarction: increased left ventricular thrombus formation in patients not treated with high-dose heparin

In a prospective non-randomized study, 229 patients with a verified first acute anterior myocardial infarction (AAMI) underwent echocardiography before discharge in order to study left ventricular (LV) thrombus formation. Antithrombotic therapy was given according to the routine of each centre. Patients receiving high-dose heparin had few LV thrombi, irrespective of warfarin therapy (6/32 vs 3/25, P ns). In patients not given heparin, however, a significantly higher prevalence of LV thrombi was found in a subgroup of patients treated with warfarin as compared to those who did not receive warfarin (8/13 vs 17/68, P 0.02). A similar, but non-significant difference was observed in patients given low-dose heparin (42% vs 27%, P ns). Within the non-heparin and low-dose heparin groups, age, infarct size, occurrence of Q-wave infarction, congestive heart failure and LV wall motion impairment did not differ between those treated or not treated with warfarin. In conclusion, high-dose heparin seems effective in the prevention of LV thrombosis irrespective of warfarin therapy after AAMI. The start of warfarin therapy in patients not receiving heparin was, however, associated with an increased prevalence of LV thrombosis.

Validity of an early postoperative baseline Doppler recording after aortic valve replacement

In 131 patients undergoing aortic valve replacement (53 bioprostheses, 78 mechanical), the pressure decrease across the prosthesis was recorded with Doppler ultrasound at a baseline study early postoperatively (mean 11 +/- 5 days) and compared with a repeat measurement 3 to 5 months later. At baseline the hemodynamic state was markedly different, with increased heart rate (89 +/- 14 vs. 74 +/- 13 beats/min, p less than 0.001) and decreased left ventricular ejection time index (367 +/- 21 vs 390 +/- 22, p less than 0.001). A minor and clinically insignificant decrease in pressure decrease with time was found. The 95% confidence interval for the difference was 0.2 to 3.0 and 0.2 to 1.7 mm Hg for the peak and the mean pressure decrease, respectively. The change in pressure decrease was statistically significant for bioprostheses (mean 16 +/- 5 vs 14 +/- 4 mm Hg, p less than 0.01) and smaller (less than or equal to 23 mm) valves (mean 17 +/- 4 vs 15 +/- 4 mm Hg, p less than 0.01), whereas no significant changes were found for mechanical valves or valves of a larger size. The change in mean pressure decrease from baseline to the second examination was within +/- 5 mm Hg for 82% of patients. It is concluded that despite a different hemodynamic state in the early postoperative period, the pressure decrease across aortic valve prostheses obtained at this time can be used as a reference for later comparison.

Half time of the diastolic aortoventricular pressure difference by continuous wave Doppler ultrasound: a measure of the severity of aortic regurgitation?

Thirty four patients with aortic regurgitation were studied by continuous wave Doppler ultrasound. In 30 of these the regurgitation was graded by cineangiography as mild, moderate, or severe and in four severe regurgitation was confirmed at operation. The half times of the aortoventricular pressure differences obtained with Doppler compared well with those obtained from pressure recordings at catheterisation. The relation between pressure half times and cineangiographic gradings of severity was not consistent. Similarly, a control group of patients without aortic regurgitation showed a wide range of the invasively recorded pressure half times which overlapped with those in patients with aortic regurgitation. This suggests that factors such as systemic vascular resistance, and aortic and left ventricular compliance can have an appreciable effect on the pressure half time. If these factors are not included the method will be of limited value, except in patients with pressure half times of less than 300 ms, when regurgitation invariably is severe. These results suggest that at present the method is of value only in recognising the patients with the most severe aortic regurgitation who need early operation.

Aortic stenosis in adults. Non-invasive estimation of pressure differences by continuous wave Doppler echocardiography

The peak and mean aortic transvalvar pressure differences measured invasively and non-invasively by continuous wave Doppler echocardiography were compared in 87 consecutive patients with aortic stenosis. The mean values were calculated from the maximal velocities of the aortic jet recorded with a spectral display of the Doppler frequency shifts and by applying a modified Bernoulli equation. Technically satisfactory velocity curves for estimating the mean pressure differences could not be obtained in three patients and invasive measurements were not obtained in two. In all patients the peak transvalvar pressure difference was calculated since the aortic jet was identified non-invasively. The peak and mean pressure differences measured invasively and non-invasively correlated well--with only minor underestimation of the pressure differences measured with the Doppler technique--regardless of age, sex, and the presence or absence of aortic valvar regurgitation, or other valvar lesions. With a systematic search for the highest velocities in the aortic jet and with on line spectral analysis of the Doppler frequencies the peak and the mean aortic pressure differences can be determined non-invasively with a high degree of precision in almost all patients.

Noninvasive estimation of valve area in patients with aortic stenosis by Doppler ultrasound and two-dimensional echocardiography

In 30 patients with aortic stenosis, 14 of whom also had significant aortic regurgitation, the velocities in the stenotic jet (V') and below the valve (V) were recorded by Doppler ultrasound. With two-dimensional echocardiography, two subvalvular areas (A) were calculated from leading-to-leading edge ("large") and trailing-to-leading edge ("inner") diameter measurements. The aortic valve area was calculated by the equation of continuity (A' = A X peak V/peak V') and by calculating stroke volume below the valve [A X integral of V (t) and dividing by the integral of V' (t) (= A"). Based on cardiac output estimations from single-plane angiographic images, Gorlin's formula was used to calculate invasive valve areas. In patients with no or mild aortic regurgitation a second invasive estimate was based on cardiac output measured by the Fick method. The best correlation was found when A' (with "large" diameter) was compared with invasive results based on cardiac output measured by the Fick method (r = .89, SEE +/- 0.12, n = 16); the worst was found when A" (with "large" diameter) was compared with invasive results based on cardiac output measurements by single-plane angiography (r = .80, SEE +/- 0.20, n = 30). The results indicate that valve area in patients with aortic stenosis can be reliably estimated noninvasively, even in those with significant aortic regurgitation.

Left ventricular systolic time intervals. A comparison between the conventional carotid pulse curve method and the doppler ultrasound method

From amplitude registration of the doppler ultrasound signal, timing of cardiac valve opening and closure may be achieved and used for the registration of the time intervals of the cardiac cycle. In 42 normal subjects and unselected patients with heart disease a comparison was made of the simultaneously derived left ventricular systolic time intervals (LVSTI) from the conventional noninvasive method of electrocardiogram, phonocardiogram and carotid pulse curve tracing and from an alternative more direct noninvasive method by use of the amplitude tracing of the doppler ultrasound signal. There was a strong correlation between the two methods for each of the different periods of the LVSTI. Differences between the pulse transmission times of curve upstroke and incisura, and possible limitations of both methods are discussed.