Hugo G. Bogren

The Variable Spectrum of Echocardiographic Manifestations of the Mitral Valve Prolapse Syndrome

The variety of echographic features associated with the mitral valve prolapse syndrome (MVPS) is not yet completely understood. Therefore, ultrasound recordings were obtained in 33 patients in whom mitral prolapse had been documented by biplane left ventricular cineangiography. Echographic abnormailities of the mitral leaflets during systole were recorded in 26/27 MVPS patients and 6/6 with ruptured chordae tendineae. In MVPS, the midsystolic mitral buckling, emphasized in early echocardiographic studies, was observed in only 12 patients. In our study, the most common aberrancy was abnormal pansystolic mitral motion in 14 patients, which in 12 was similar to the pansystolic bowing observed in all six patients with torn chordae. An additional echographic abnormality in MVPS was localized mitral collapse throughout systole in 10/14 patients with pansystolic prolapse; this finding was the most striking defect noted in five, in two of whom it was the only disturbance. Phonocardiography in MVPS showed typical midsystolic click and/or late systolic murmur in only 15/26 patients of whom ten had midsystolic mitral buckling. A variety of systolic clicks and/or murmurs occurred in the 14 patients with generalized bowing and/or localized collapse throughout systole on echocardiography. Thus, the mitral echographic spectrum of MVPS is comprised of three different abnormal patterns of systolic prolapse: buckling in midsystole, pansystolic bowing, and pansystolic collapse. These echocardiographic disorders commonly occur in the absence of classical auscultatory findings in MVPS and the most frequent abnormality on ultrasound is pansystolic bowing of both mitral leaflets.

Pulmonary artery distensibility and blood flow patterns: A magnetic resonance study of normal subjects and of patients with pulmonary arterial hypertension

Abstract Pulmonary artery distensibility was studied with spin-echo magnetic resonance imaging in 20 normal subjects of variable age and in four patients with pulmonary arterial hypertension. The distensibility was found to be significantly lower (8%) in patients with pulmonary arterial hypertension than it was in normal subjects (23%). No age-related difference occurred. Magnetic resonance velocity mapping of the pulmonary artery blood flow was performed in 26 normal subjects—11 had mapping in the mid pulmonary artery, 15 had mapping in the distal pulmonary artery, and mapping in the four patients with pulmonary arterial hypertension was in the mid pulmonary artery. The pulmonary artery flow volume was compared with aortic flow and left ventricular stroke volume and a very good correlation was found. A retrograde flow of 2% occurred in the normal subjects serving to close the pulmonic valve. Antegrade plug flow occurred in most normal subjects but varied among individuals. There were also other variations in the flow pattern among normal individuals. All patients with pulmonary arterial hypertension had a markedly irregular ante- and retrograde flow and a large retrograde flow (average 26%). Magnetic resonance imaging offers a noninvasive way to evaluate pulmonary arterial hypertension as well as to quantitate pulmonary and aortic flows in, for example, left-to-right shunts.

4D magnetic resonance velocity mapping of blood flow patterns in the aorta in young vs. elderly normal subjects.

Four‐dimensional magnetic resonance MR velocity mapping was developed to study normal flow patterns in the thoracic aorta using time‐resolved cardiac gated three‐directional velocity data. Sixteen normal subjects were studied, one young group (average age 31 years) and one group with elderly people (average age 72 years). Blood flowed in a right‐handed helix from the ascending aorta to the aortic arch. A straight flow pattern or a left‐handed helix was seen in the descending aorta. Blood flow was never parabolic. Blood flowed forward in early systole, retrograde in mid‐to‐end systole, and forward again in diastole in all subjects as a basic pattern. Continuous retrograde flow over a long distance was not seen, but blood entered a retrograde flow column at various levels. In young people blood passed from the aortic valve to the mid‐descending aorta in less than one heartbeat. In people in their sixties it took two heartbeats and in people older than 78 years, it took three heartbeats. The maximum systolic forward velocities were higher in young subjects than in elderly while the retrograde velocities were lower. J. Magn. Reson. Imaging 1999;10:861–869.

The function of the aorta in ischemic heart disease: A magnetic resonance and angiographic study of aortic compliance and blood flow patterns

Regional compliance of the ascending aorta, aortic arch, and the descending aorta was measured in 70 normal subjects at varying ages, in 17 patients with coronary artery disease (10 coronary artery disease patients, 3 with syndrome X), and in 13 trained athletes using magnetic resonance imaging. Ascending aortic compliance was measured angiographically in 22 patients with documented coronary artery disease and in 11 patients with syndrome X. Magnetic resonance velocity mapping was used in six patients with documented coronary artery disease and in three patients with syndrome X to study two-dimensional velocity profiles in the proximal and mid-ascending aorta and to quantify both forward and reverse flow. The measurements were compared with earlier published measurements from 24 normal subjects. It was found that patients with ischemic heart disease or syndrome X had decreased or no measurable aortic compliance and that they had significantly reduced or abnormal ascending aortic reverse flow likely to cause reduced coronary artery flow. A new theory is advanced that decreased myocardial perfusion leading to ischemic heart disease has two sources: (1) insufficient blood flow into the coronary artery inlet due to abnormal aortic function and independent of coronary artery stenosis and (2) local coronary artery stenosis. Observations supporting the theory are presented.

Quantitation of antegrade and retrograde blood flow in the human aorta by magnetic resonance velocity mapping

Magnetic resonance velocity mapping was used in 24 normal subjects to study two-dimensional velocity profiles in the proximal and mid-ascending aorta, and to quantify both forward and reverse flow. The aortic flow measurements were validated by comparison with left ventricular stroke volume in all subjects and by comparison with pulmonary flow measurements in 12. Agreement was good with standard errors of the estimate of 7.8 and 7.1 ml, and correlation coefficients of 0.93 and 0.95, respectively. Systolic velocity maps were similar in the proximal aorta and the mid-ascending aorta, with maximum early systolic flow along the left posterior wall. Toward the end of systole and throughout diastole, a channel of reverse flow developed in the same region in the mid-ascending aorta, but in the proximal aorta it split to enter the sinuses of Valsalva, predominantly the left and the right coronary sinuses. Mean percentage ratio of retrograde-to-antegrade flow was 6.3%, with the majority of retrograde flow occurring in early diastole. The findings suggest that the retrograde flow is related to coronary artery flow and it is possible that aortic disease, which is known to influence aortic flow patterns, may also influence coronary flow.

Electrocardiographic and Cineangiographic Correlations in Assessment of the Location, Nature and Extent of Abnormal Left Ventricular Segmental Contraction in Coronary Artery Disease

The relationship between the resting electrocardiogram and left ventricular contractile pattern, as documented by angiography, was evaluated in 123 patients with coronary artery disease who underwent left ventriculography. Dyssynergy was present in 73/77 (95%) patients with pathologic Q waves on ECG recordings in contrast to 11/46 ( 24%; P < 0.01) without Q waves. The location of Q waves correlated well with the site of abnormal ventricular motion: antero-apical dyssynergy in 40/40 (100%) patients with anterior myocardial infarction (MI) and infero-apical dyssynergy in 25/28 (89%) with inferior MI. Four contraction patterns were defined: 1) normal motion-39 patients (35 without Q waves, four with inferior or posterior Q waves); 2) segmental hypokinesis-37 patients (six without Q, 31 with Q); 3) segmental akinesis-26 patients (four without Q, 22 with Q); and 4) localized dyskinesis-aneurysm in 21 patients (only one without Q, 20 with Q). The presence of ST elevation and T wave inversion (ST↑ - T↓) along with Q waves were associated with dyskinesis or akinesis in 18/19 (95%) patients. The Q wave location reflected the type of dyssynergy: 32/40 (80%) patients with anterior MI had akinesis or dyskinesis, while 18/28 (64%) patients with inferior MI exhibited hypokinesis. Lateral extension of the Q wave in an anterior MI was related to the dyssynergy type (average V lead: 4.9 in dyskinesis and 3.3 in hypokinesis; P < 0.05) and extent (dyssynergy area /LV silhouette: 31% with Q to V3 and 58% to V5 or V6; P < 0.05). Dyssynergy area was larger in isolated anterior than inferior MI (42% and 23% of LV perimeter; P < 0.05) and largest in the anterior-inferior MI (68%; P < 0.05). Dyssynergy was more extensive with Q and ST↑-T↓ than with Q alone (48% and 33% LV perimeter; P < 0.05). Thus, specific QRS and ST-T wave alterations, when monitoring coronary disease, accurately predict characteristics of LV dyssynergy: Q identifies its presence and location and Q with ST↑-T↓ estimates its nature and extent.

Magnetic resonance velocity vector mapping of blood flow in thoracic aortic aneurysms and grafts

Magnetic resonance imaging with multidirectional cine velocity mapping was used to study relationships between aortic blood flow patterns and the geometry of thoracic aortic aneurysms and grafts. Ten patients with 13 thoracic aortic aneurysms, single or multiple, or grafts (4) participated in the study. The causes of disease were atherosclerosis (4), Marfans syndrome (2), trauma (1), and unknown (1), and there were two dissections. Spin-echo imaging and cine velocity mapping in 10 mm thick slices with vertical and horizontal velocity encoding were done. Maps of the two velocity components were processed into multiple computer-generated streaks whose orientation and length corresponded to velocity vectors in the chosen plane. The dynamic arrow maps were compared with previously reported aortic arrow maps from normal subjects. The forward flow occupied the entire lumen in the normal aorta in systole and small vortices were only present in the sinuses of Valsalva. Atherosclerotic aneurysms in the ascending aorta were located at the anterior right and had oblique, eccentric jet flows that created a large secondary vortex in the aneurysm. Patients with Marfans syndrome had a central jet and two large vortices, one on each side. All other aneurysms, dissections, and grafts had irregular flows and vortices not seen in normal subjects. Magnetic resonance imaging with multidirectional velocity mapping is a powerful noninvasive tool to assess morphologic features and disturbed blood flow in aortic aneurysms and grafts. Recognizably altered flow patterns were found to be associated with altered vessel geometry. The significance of this requires further investigation.

Evaluation of transluminal angioplasty of chronic coronary artery stenosis. Value and limitations assessed in fresh human cadaver hearts.

The possibility of increasing reduced blood flow in atherosclerotic coronary obstruction by catheter balloon dilatation offers a nonsurgical approach to relieve clinical coronary stenosis. To assess the ability of effectively dilating such diseased vessels by transluminal angloplasty, we used the Grlintzig balloontipped catheter in 12 fresh human cadaver hearts in which the intervention was performed in 21 noncalcifled stenotic areas, including each of the three major coronary arteries. Quantitative coronary arteriography documented decreased obstruction of each lesion; luminal diameter increased 58% (1.9 ± 0.2 mm to 2.8 ± 0.3; p < 0.001) and luminal diameter relative to the most proximal normal coronary segment diminished 61% (46 ± 4% to 18 ± 3%; p < 0.001). Angioplasty was most successfully applied in proximal, discrete, noncalcified lesions of the right and left anterior descending coronaries; calcified, tortuous, middle and distal lesions and the left circumflex coronary were entered with difficulty or unapproachable. Histologic examination revealed microanatomic changes, most often endothelial disruption and atheroma compression, but no serious vascular tears. Dilatation beyond normal coronary diameter caused vessel rupture. This study extends elucidation of the value and limitations of percutaneous transduminal angioplasty in the clinical use of this technique in selected patients for relieving coronary obstruction without surgery.

Four-dimensional magnetic resonance velocity mapping of blood flow patterns in the aorta in patients with atherosclerotic coronary artery disease compared to age-matched normal subjects.

To test the hypothesis that age and atherosclerotic coronary artery disease (CAD) may influence aortic blood flow patterns.

Identification and localization of aneurysms of the ascending aorta by cross-sectional echocardiography.

Although the ascending aorta may be readily examined by cross-sectional echocardiography (2-D), no data are available regarding the ability of 2-D to detect and localize aneurysms of this structure. Therefore, we compared M-mode and 2-D echograms to cineangiograms of the aorta in 32 normal subjects and 12 patients with aortic aneurysms. Measurement of aortic width was performed in the longitudinal axis just above the sinus of Valsalva in normal subjects and at the point of maximal aortic width in aneurysm patients. A good correlation (r = 0.88) was observed between M-mode and angiographic measurements of aortic diameter for all subjects. However, M-mode and angiographic values of aortic diameter correlated less well (r = 0.55) in patients with aortic aneurysms. Values for aortic size by cineangiogram and 2-D were similar for both normal subjects (mean 34 and 33 mm, respectively) and aneurysm patients (62 and 65 mm, respectively). There was an excellent correlation (r = 0.94) between cineangiogram and 2-D for all patients evaluated, and for patients with aneurysms (r = 0.91). By 2-D we detected enlargement of the aorta in all 12 aneurysm patients, and mean aortic size by 2-D was greater (63 mm) than in normal subjects (33 mm) (p>0.001). The site and nature of aneurysm was accurately identified by 2-D in all patients. Thus, 2-D provides an accurate noninvasive modality for the detection and localization of aneurysms of ascending aorta.