The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

Measurements of mean left ventricular (LV) and regional myocardial blood flow rates were made at rest in 161 patients with 133Xe and a multiplecrystal scintillation camera. Myocardial perfusion rates were correlated with assessments of the degree of coronary artery disease made from the arteriograms obtained during the same studies. In patients with normal coronary arteries without heart failure, the presence of hypertension, aortic stenosis, or aortic insufficiency was not associated with changes in mean LV perfusion from the control value of 61+/-7 ml/100 g-min. However, mean LV perfusion was significantly reduced in patients with normal coronary arteries who had cariomyopathy and impaired ventricular performance. Mean LV perfusion was not significantly different from control values in patients with "mild" coronary artery disease (less than 50% obstruction) or in patients with significant isolated disease (greater than 50% obstruction) of the left anterior descending (lad) artery. Significant reductions in mean LV perfusion were found in patients with greater than 50% obstruction of two coronary arteries (LAD + right or LAD + circumflex) and in patients with triple-vessel disease. The average perfusion rate for regions distal to LAD obstructions in patients with isolated LAD disease was not lower than the LAD perfusion in control patients, but was significantly reduced in patients with LAD + right coronary artery disease (43+/-14 ml/100 g-min). In the latter group average perfusion distal to the LAD lesion was significantly lower than the average regional perfusion rate for the remainder of the LV. However, the mean blood flow rate for the remainder of the LV was also significantly lower than control values despite the lack of significant circumflex disease. The data demonstrate that the presence of radiographically "mild" or significant isolated LAD coronary disease is not associated with reductions in mean LV perfusion at rest, but that mean LV perfusion is reduced in the presence of significant disease of two or three coronary artieries. None of the patients experienced angina during the resting studies and most had clinical evidence of ventricular failure. The observation of depressed LV perfusion in this group, as in the patients with cardiomyopathy, raises the possibility that a lowered resting blood supply may be adequate for a reduced level of performance of a diseased ventricle. The lack of selective reductions of regional perfusion at rest in the majority of the patients with LAD lesions suggests that regional myocardial blood flow must be measured during an intervention which increases myocardial oxygen consumption in order to assess the physiological significance of lesions which are observed at coronary arteriography.

The clinical, radiologic, and pathologic characterization of benign hepatic neoplasms. Alleged association with oral contraceptives.

Poor histopathologic documentation and confusing terminology have caused focal nodular hyperplasia (FNH) and liver cell adenoma (LCA) to be categorized together as "benign hepatomas." FNH and LCA are distinguishable grossly, microscopically, and ultrastructurally. In a majority of instances they may be differentiated by combined angiography and liver scan: FNH is hypervascular and exhibits normal uptake on scan whereas LCA is hypovascular and cold on scan. FNH almost always follows a benign course, rarely undergoing hemorrhagic necrosis and rupture. FNH does not possess malignant potential; the prognosis, even if unexcised, is excellent. Resection is indicated only if FNH is symptomatic. LCA often ruptures and its malignant potential remains uncertain; the prognosis is guarded and resection is indicated. The literature reported association between FNH and oral contraceptives is anecdotal. However, the recent marked increase in the incidence of LCA's, their almost exclusive occurrence in young women, and the consistent hormonal history strongly suggests an association between oral contraceptive use and LCA's, although here too, statistical evidence is lacking. Prognostic and therapeutic considerations mandate that a clear distinction be made between FNH and LCA.

Measurement of regional myocardial blood flow in man: description and critique of the method using xenon-133 and a scintillation camera.

A method has been devised to measure regional myocardial blood flow in man. The approach consists of selective injection of xenon-133 into a coronary artery and the external monitoring of radioisotope washout curves from multiple areas of the myocardium with a multiple crystal scintillation camera. Rate constants of isotope washout are calculated using a monoexponential model, and the capillary blood flow rates in multiple regions of the heart are calculated by the Kety formula. The pattern of perfusion rates is related to the coronary arteriogram obtained in the same study. Myocardial perfusion patterns obtained in patients with and without coronary artery disease and during atrial pacing are given, as well as examples of results obtained in myocardial aneurysms, in regions of ischemic myocardium supplied by collateral vessels and after tracer injection into an aortocoronary bypass graft. Advantages of the method are discussed along with limitations related to the tracer, the scintillation camera, the form of mathematical analysis and the three dimensional nature of the heart.

Validation of the angiographic accuracy of digital left ventriculography.

Digital subtraction angiography enhances the contrast to background signal, enabling the performance of angiography with reduced doses of contrast medium. The objectives of the present study were (1) to validate the accuracy of digital left ventriculography for measurement of left ventricular volumes and segmental contraction; and (2) to compare the hemodynamic effects resulting from low-and high-dose intraventricular contrast injections. Twenty-eight patients underwent digital left ventriculography, performed by intraventricular injection of 7 ml of contrast medium diluted in saline solution, followed by conventional cineangiography of the left ventricle performed with 45 ml of undiluted contrast medium. Left ventricular volumes calculated from digital ventriculograms correlated well with volumes calculated from conventional ventriculograms: end-diastolic volume (r = 0.97, standard error of estimate [SEE] 23.4 ml; end-systolic volume (r = 0.97, SEE 15.4 ml); stroke volume (r = 0.95, SEE 14.7 ml); and ejection fraction (r = 0.97, SEE 3.8%). Segmental left ventricular contraction, measured as percent chordal shortening of hemiaxes, correlated moderately well (r = 0.81, SEE 11.5%). After injection of undiluted contrast medium, left ventricular systolic pressure decreased (133 +/- 31 to 123.5 +/- 27 mm Hg; p less than 0.01) and left ventricular end-diastolic pressure increased (12.0 +/- 7 to 16.9 +/- 10 mm Hg; p less than 0.001). Left ventricular systolic and end-diastolic pressures did not change significantly after injection of diluted contrast medium, and patients had no discomfort. Thus, digital subtraction angiography permits the performance of left ventriculography with markedly reduced doses of contrast medium, obviating the hemodynamic effects resulting from injection of conventional doses of contrast medium. This new approach to left ventriculography provides high resolution ventriculograms for accurate measurement of left ventricular volumes, stroke volume, and ejection fraction.

Percutaneous intraaortic balloon insertion.

A new single chambered percutaneous intraaortic balloon has been constructed around a central guidewire. The balloon can be wrapped around the guidewire, enabling its insertion into the femoral artery through a 12F sheath inserted with the conventional Seldinger technique. Percutaneous intraaortic balloon insertion has been performed in 27 patients (mean age 58 years) for a variety of medical and surgical indications. Percutaneous balloons could not be advanced into the aorta in two patients (7.4 percent) with severe bilateral aortoiliac occlusive disease. In all 25 patients undergoing intraaortic balloon pumping satisfactory circulatory support was achieved, and 21 (84 percent) of the patients survived to be discharged from the hospital. The mean duration of intraaortic balloon pumping was 3.5 days. Percutaneous intraaortic balloon insertion requires less than 5 minutes and has been successfully performed in the cardiac catheterization laboratory, coronary care unit, operating room and recovery room. After direct balloon removal, external pressure was applied for 30 minutes. No patient experienced hematoma of the groin, aortic dissection, compromised distal pulses or late wound complications. Percutaneous balloon insertion permits the rapid institution of circulatory support and broadens the medical and surgical applications of intraaortic balloon pumping.

Studies of regional myocardial blood flow: results in patients with left anterior descending coronary artery disease.

Measurements of regional myocardial blood flow have been performed rapidly and safely in man at the time of coronary arteriography. Xenon-133 was injected into the coronary artery and estimates of myocardial capillary perfusion were made by computer analysis of the multiple precordial tracer washout curves recorded with a scintillation camera. Blood flow rates/100 g/min in different areas of the heart were calculated by the Schmidt-Kety formula, using an assumed partition coefficient, and were related to the coronary vascular lesions by landmarks provided by the arteriograms. The flow significance of lesions was assessed by making measurements at rest and during interventions that increase coronary blood flow. Perfusion was also estimated in areas supplied by collateral vessels, and regions of scar were detected from the initial distribution of peak tracer activity. In patients with less than 50% obstructions apparent on coronary arteriograms and in those with greater than 50% isolated left anterior descending lesions average mean left ventricular (LV) myocardial perfusion values were not reduced below values found in patients with normal coronary arteries and normal cardiac function. However, in patients with significant two-vessel disease (LAD + right, LAD + circ) mean LV perfusion was significantly reduced. Average regional myocardial perfusion distal to significant lesions was not selectively reduced below the remainder of the ventricle unless the lesions were 100% obstructions. However, both total and distal regional myocardial perfusion increased less in 12 patients with greater than 50% lesions than in 12 others with normal arteriograms or less than 50% lesions. Subnormal flow responses in all of the former group were associated with angina pectoris compared with no angina in the latter. The studies indicate the potential utility of the measurements of regional myocardial blood flow in the evaluation of patients with ischemic heart disease who are potential candidates for myocardial revascularization procedures.

Renovascular hypertension following surgical repair of dissecting aneurysm of the thoracic aorta.

A critically ill patient with refractory renovascular hypertension following successful intrathoracic repair of a type I aortic dissection was treated successfully with gelfoam embolization of the left kidney. Renal artery stenosis secondary to aortic dissection can exacerbate pre-existent hypertension in the preoperative or postoperative periods and can be diagnosed angiographically. Unilateral renal artery embolization may provide a safe alternative to nephrectomy for renovascular hypertension in cases where surgery is not feasible.

Percutaneous intraaortic balloon pumping: initial clinical experience.

A new intraaortic balloon is described that can be inserted percutaneously through a 12F sheath by the standard Seldinger technique. Insertion and removal are rapid, and the hemodynamics of balloon pumping are similar to our previous clinical experience with standard single- and dual-chambered intraaortic balloons. The initial clinical experience is detailed.

Guide wire thrombogenicity measured by fibrinopeptide A radioimmunoassay.

A radioimmunoassay for measurement of canine fibrinopeptide A, which provides a quantitative index of thrombin action on canine fibrinogen, was applied to measurements of the thrombogenicity of angiographic guide wires. Benzalkonium-heparin-treated Teflon-coated, untreated Teflon-coated, and uncoated stainless steel wires were compared in an experiment in dogs which closely simulated the use of these wires in humans. During the first 4 min after insertion, the benzalkonium-heparin-treated Teflon-coated wire was associated with significantly greater systemic levels of fibrinopeptide A than were either Teflon-coated or stainless steel wires. Beyond 10 min, markedly increased levels of fibrinopeptide A were measured in association with these latter two wires compared to the benzalkonium-heparin-treated Teflon-coated wire. Both the early rises in fibrinopeptide A associated with the benzalkonium-heparin-treated Teflon-coated wire and the late increases in fibrinopeptide A associated with the Teflon-coated and uncoated stainless steel wires could be eliminated by prior systemic administration of low dose heparin (40U/kg). These studies suggest that, at least in regard to activation of the plasma clotting system, the benzalkonium-heparin treatment offered no advantages over the other wires tested in terms of reduced thrombogenicity within the critical 10 min following insertion. No difference could be discerned between uncoated stainless steel wires and Teflon-coated stainless steel guide wires in this test.

Azotemia caused by renal artery stenosis: treatment by percutaneous angioplasty.

Percutaneous angioplasty of the renal artery was performed in 79 patients who had stable or climbing serum creatinine levels greater than 1.7 mg/dl and hemodynamically significant stenosis of the renal artery. Patients who had nonrenal causes of azotemia, nephropathy caused by iodinated contrast material, or serum creatinine levels that were declining while the patients were receiving medical therapy before angioplasty were excluded from the study. Angioplasty resulted in a significant (greater than 20%) decline in the level of serum creatinine (average, 2.7 mg/dl before to 1.7 mg/dl after) in 43% of these patients during an average follow-up period of 16 months. A significant decrease in the level of serum creatinine was seen in 61% of patients with bilateral stenosis, 38% of patients with unilateral stenosis with absent contralateral renal blood flow, and 38% of patients with unilateral stenosis and normal contralateral renal blood flow. Recapture of lost nephron function was least successful in patients whose levels of serum creatinine were greater than 4.0 mg/dl (14%); this included one (11%) of nine patients who were already on hemodialysis. We conclude that angioplasty of the renal artery can play a major role in the treatment of patients who have mild azotemia and bilateral stenosis of the renal artery. It is less successful in treatment of patients who have severe azotemia and those who have unilateral disease.

Percutaneous coronary angioplasty: technique, indications, and results.

The simplicity, safety, and economic advantages of percutaneous transluminal coronary angioplasty (PTCA) over coronary bypass surgery have encouraged its wide use as an alternative revascularization procedure. Four major problem areas require solutions before the technique fulfills its potential. First, PTCA technology requires further development to enhance success rates in severe, old, calcified lesions and in chronic total occlusions. Second, acute vessel reclosure needs intensive study to determine how this important complication can be foreseen and effectively managed if not avoided entirely. Third, effective treatment strategies for patients with multivessel disease require definition. Finally, the problem of late lesion recurrence needs to be solved. Until these goals are achieved, the general practice of PTCA should be restricted to treatment of early-stage coronary artery disease, single-vessel, or discrete two- and three-vessel disease.