Percutaneous coronary intervention in unprotected left main disease: a status report.

Percutaneous coronary intervention (PCI) of the unprotected left main (LM) artery is currently not recommended as a routine procedure based on the history of inferior outcomes of LM percutaneous transluminal coronary angioplasty and bare metal stenting. Instead, surgical revascularization (coronary artery bypass grafting, CABG) is considered to be the gold standard. There is renewed interest in LM-PCI because of improved outcomes of PCI utilizing drug eluting stents (DES) in multiple randomized trials. Several single-center non-randomized registries have evaluated the role of DES for LM-PCI. Data suggest a low mortality and target vessel failure of ostial LM or mid-shaft lesions in contrast to bifurcation lesions, which frequently require complex dual stenting techniques. The complex PCI in the bifurcation is associated with the increased occurrence of target vessel failure ranging from 2% and 38%. The rate of target vessel failure in bifurcation lesions is less in patients in whom the circumflex ostium is not involved so that single cross over stent is suitable. Current recommendations call for a follow-up angiography at 4-6 months to detect LM restenosis prior to a potentially fatal clinical event. The question of the duration of dual antiplatelet therapy in patients who underwent LM-PCI is unanswered. More registry data and randomized trials are needed before unprotected LM-PCI can be routinely offered to patients as an alternative to CABG.

Dislodgement of a vein graft thrombus by angiographic injection of native coronary artery.

A case of retrograde dislodgement of thrombus in a saphenous vein graft during injection of the native right coronary artery is presented. Attention to this previously undescribed complication may allow for timely treatment with emergency surgery or thrombolysis.

Relation of P-S4 interval to left ventricular end-diastolic pressure.

Reports have suggested that the interval between P wave onset and the fourth heart sound (P-S4 interval) reflects changes in left ventricular myocardial stiffness. We made simultaneous measurements of the P-S4 or atrial electrogram to S4 (A-S4) interval and left ventricular pressure in 19 patients with coronary artery disease who were studied before and after atrial pacing. Thirteen patients developed angina accompanied by significant rises in their end-diastolic pressure and a consistent decrease in P-S4 or A-S4 interval; whereas the six patients who had atrial pacing without the development of angina had no change in end-diastolic pressure, P-S4, or A-S4 interval. The resting data showed in inverse correlation between left ventricular end-diastolic pressure and the P-S4 interval. In addition, the P-S4 interval let us discriminate between patients with normal and abnormal end-diastolic pressure (greater than 15 mmHg).

In vitro quantitation of canine left ventricular volume by phased-array sector scan.

Ultrasonic sector-scan images can delineate the entire circumference of the canine left ventricle in vitro. This study was undertaken to (1) assess the accuracy of sector scanning for estimating canine left ventricular volume in vitro compared to volume estimates by M-mode echo in the same hearts and (2) determine the optimal techniques for estimating left ventricular volume with sector scanning. 16 volumes (1 volume from 8 hearts and 2 volumes from 4 hearts) were estimated by obtaining sector-scan images from orthogonal long-axis, short-axis and apical views. The sector-scan volumes were calculated by single and biplane area-length methods, as well as biplane Simpson's rule methods, and compared to measured left ventricular volumes. M-mode echo volumes were calculated by cubing the mid-ventricular minor-axis diameter. Sector-scan views containing a long-axis dimension plus the short-axis dimension of the left ventricle had a high correlation with true left ventricular volume while sector-scan views not containing a long-axis view showed only a fair correlation with volume. M-mode echo produced a poor estimate of the true left ventricular volume. It is concluded that (1) sector scanning can provide highly accurate in vitro volume estimates of canine left ventricles which is superior to estimates derived by M-mode echocardiographic methods and (2) the optimal sector-scan views for estimating left ventricular volume are those that make the fewest assumptions about left ventricular geometry and have the greatest amount of dimensional information.

Single and two dimensional echocardiographic features of the interatrial septum in normal subjects and patients with an atrial septal defect.

The interatrial septum is one of the least studied structures in M mode echocardiography. Two dimensional echocardiography has made it possible to record simultaneous M mode and two dimensional echocardiograms. Such studies were performed in 10 normal subjects and in 9 patients with a secundum atrial septal defect. In the short axis view of the base of the heart, the interatrial septum was visualized in the two dimensional studies as a linear echo running from the posterior aortic wall to the posterior atrial wall and in the M mode records as a series of dense echoes posterior to the aorta. The great variability in echo dropout of the interatrial septum made it impossible to distinguish the normal subjects from the patients with atrial septal defect. The dense echoes of the interial septum in the M mode records gave the false impression that they were filling the left atrium. These data indicate that (1) a secundum atrial septal defect cannot be reliably differentiated from a normal septum using these echocardiographic methods, and (2) the medial location of the interatrial septum should be appreciated so that it will not be confused with a left atrial mass.

Two-dimensional echocardiographic features of bicuspid aortic valve.

The two-dimensional cross-sectional echocardiographic diagnosis of bicuspid aortic valves is described and compared with results of M-mode echocardiograms. Aortic valve anatomy was determined in 19 selected patients by angiography, and confirmed in five by direct surgical visualization. Using an eccentricity index (EI) of 1.3 or greater as diagnostic of bicuspid aortic valve, M-mode correctly identified anatomy in 14 of 19 valves (74 percent), although EI varied in several patients. For two-dimensional diagnosis of bicuspid aortic valve, short axis cross section was preferred, and criteria included number of cusps seen in real time motion, irregularity of folding of cusp margins, and location of commissural insertions. Two-dimensional echocardiography correctly identified anatomy in 18 of 19 valves (95 percent). Long axis cross section disclosed valvular doming in all 8 patients in whom doming was observed angiographically, correlating with hemodynamic findings. Two-dimensional echocardiography aids in the detection of bicuspid aortic valve in a suspected population, can give an estimate of valve gradients, and explains variability in M-mode findings. As such, two-dimensional echocardiography is a valuable tool in the noninvasive diagnosis of the bicuspid aortic valve.

Two dimensional echocardiographic assessment of patients with bioprosthetic valves.

The clinical utility of two dimensional echocardiography in assessing bioprosthetic and left ventricular function was studied in 40 consecutive patients 1 week to 60 months after valve replacement surgery. These patients were referred to obtain normal baseline studies as well as to evaluate complications:suspected endocarditis, embolic phenomena and congestive heart failure of unknown cause. Independent M mode echocardiograms were also obtained in each patient. Confirmation of ultrasonic studies was by cardiac catheterization with angiography, surgery and pathologic study in 10 patients; cardiac catheterization with angiography alone in 7 patients; surgery and pathologic study in 3 patients; autopsy in 3 patients; blood cultures to confirm or exclude endocarditis in 10 patients; and confirmation on clinical grounds in 7 patients. Technically adequate two dimensional studies were recorded in 39 of 40 subjects. Two dimensional echocardiography accurately assessed 15 of 16 patients with an abnormal bioprosthetic valve and a normal left ventricle (1 of 16 patients had a false positive two dimensional echocardiogram); 8 of 8 patients suspected to have prosthetic valve or left ventricular dysfunction but who were normal; 7 of 7 patients with a normal prosthesis and an abnormal left ventricle; the one patient with an abnormal valve and left ventricle; and 7 of 7 clinically normal patients who were referred for baseline studies. In summary, the two-dimensional echocardiogram demonstrated a 97 percent diagnostic accuracy rate which was significantly greater than the 67 percent (P less than 0.001) for M mode echocardiography in the same group of patients. It is concluded that two dimensional echocardiography has excellent diagnostic accuracy in assessing bioprosthetic and left ventricular function and is superior to M mode echocardiography in evaluating patients after such valve replacement.

Single and two-dimensional echocardiographic visualization of the effects of septal myectomy in idiopathic hypertrophic subaortic stenosis.

Although the postoperative hemodynamic and echocardiographic features of idiopathic hypertrophic subaortic stenosis have been studied, the expected consistent postoperative thinning of the interventricular septum has not been reported. In this study, the short-term effects of septal myectomy were evaluated in 16 patients. All patients were assessed with pre- and postoperative hemodynamic studies and M-mode echocardiograms, and six of the 16 patients had pre- and postoperative two-dimensional echocardiograms. The mean resting preoperative gradient of 74 mm Hg (range 10--190 mm Hg), which fell to a mean resting postoperative gradient of 8 mm Hg (range 0--25 mm Hg), was associated with decreased end-diastolic interventricular septal thickness at the midventricular level in 14 of 16 patients and at the subaortic level in 16 of 16 patients by M-mode echocardiography. The group also demonstrated changes in left ventricular outflow tract configuration and dimension, mitral valve systolic anterior motion, mitral E-F0 slope and left ventricular percent fractional shortening by both M-mode and two-dimensional studies. In the two patients who did not show midventricular septal thinning on M-mode echocardiography, the two-dimensional echocardiograms revealed that the area of myectomy extended only through the subaortic region and not down to the midventricular septum. Thus, we have observed consistent postmyectomy septal thinning at both the midventricular and subaortic levels by M-mode echo. By defining the geometry of the septal myectomy in vivo with two-dimensional echocardiography, we can better interpret M-mode studies and identify factors that influence echocardiographic visualization of the region of myectomy.

Left ventricular-coronary sinus fistula following repeated mitral valve replacements.

After mitral valve replacement, symptomatic deterioration and new murmurs characterstistic of atrioventricular valvular regurgitation are usually the result of periprosthetic leaks or prosthetic dysfunction with or without endocarditis. In the case which we are reporting, an iatrogenic fistula between the left ventricle and coronary sinus was responsible for the murmur and symptoms. This type of shunt has not been previously reported. Thorough debridement of the anulus is necessary during mitral valve replacement; additionally, previously implanted prostheses are occasionally embedded in the endocardial wall and must be excised. Hematoma in the atrioventricular groove and perforations of the posterior left ventricular wall are widely recognized complications of mitral valve replacement. Similar mechanisms of injury can cause other problems such as left ventricular-right atrial communications and the unique anatomic shunt described in this report.