Fractional flow reserve compared with intravascular ultrasound guidance for optimizing stent deployment.

BACKGROUND: Determination of fractional flow reserve (FFR) has been proposed as a means to assess stent deployment. In this prospective, multicenter trial, we evaluate the use of FFR to optimize stenting by comparing it with standard intravascular ultrasound (IVUS) criteria. METHODS AND RESULTS: Eighty-four stable patients with isolated coronary lesions underwent coronary stent deployment starting at 10 atm and increased serially by 2 atm until the FFR was >/=0.94 or 16 atm was achieved. IVUS was then performed. FFR was measured with a coronary pressure wire with intracoronary adenosine to induce hyperemia. The diagnostic characteristics of an FFR <0.94 to predict suboptimal stent expansion by IVUS, defined in both absolute and relative terms, were calculated. Over a range of IVUS criteria, the highest sensitivity, specificity, and predictive accuracy of FFR were 80%, 30%, and 42%, respectively. Receiver operator characteristic analysis defined an optimal FFR cut point at >/=0.96; at this threshold, the sensitivity, specificity, and predictive accuracy of FFR were 75%, 58%, and 62%, respectively (P=0.03 for comparison of predictive accuracy, P=0.01 for concordance between FFR and IVUS). The negative predictive value was 88%. Significantly better diagnostic performance was achieved in a subgroup that received higher doses (>30 microgram) of intracoronary adenosine during pressure measurements, suggesting that FFR might be overestimated in the other group. CONCLUSIONS: A fractional flow reserve <0.96, measured after stent deployment, predicts a suboptimal result based on validated intravascular ultrasound criteria; however, an FFR >/=0.96 does not reliably predict an optimal stent result. Higher doses of intracoronary adenosine than previously used to measure FFR improve these results.

Final results of the Can Routine Ultrasound Influence Stent Expansion (CRUISE) study.

BACKGROUND: Intravascular ultrasound (IVUS) can assess stent geometry more accurately than angiography. Several studies have demonstrated that the degree of stent expansion as measured by IVUS directly correlated to clinical outcome. However, it is unclear if routine ultrasound guidance of stent implantation improves clinical outcome as compared with angiographic guidance alone. METHODS AND RESULTS: The CRUISE (Can Routine Ultrasound Influence Stent Expansion) study, a multicenter study IVUS substudy of the Stent Anti-thrombotic Regimen Study, was designed to assess the impact of IVUS on stent deployment in the high-pressure era. Nine centers were prospectively assigned to stent deployment with the use of ultrasound guidance and 7 centers to angiographic guidance alone with documentary (blinded) IVUS at the conclusion of the procedure. A total of 525 patients were enrolled with completed quantitative coronary angiography, quantitative coronary ultrasound, and clinical events adjudicated at 9 months for 499 patients. The IVUS-guided group had a larger minimal lumen diameter (2.9+/-0.4 versus 2.7+/-0. 5 mm, P<0.001) by quantitative coronary angiography and a larger minimal stent area (7.78+/-1.72 versus 7.06+/-2.13 mm(2), P<0.001) by quantitative coronary ultrasound. Target vessel revascularization, defined as clinically driven repeat interventional or surgical therapy of the index vessel at 9 month-follow-up, occurred significantly less frequently in the IVUS-guided group (8.5% versus 15.3%, P<0.05; relative reduction of 44%). CONCLUSIONS: These data suggest that ultrasound guidance of stent implantation may result in more effective stent expansion compared with angiographic guidance alone.

Myocardial risk area defined by technetium-99m sestamibi imaging during percutaneous transluminal coronary angioplasty: comparison with coronary angiography.

OBJECTIVES: The purpose of this study was to compare the assessment of myocardial area at risk in patients with coronary artery stenosis by coronary angiography and quantitative myocardial perfusion imaging with technetium-99m sestamibi. BACKGROUND: Decisions concerning patient management frequently rely on semiquantitative angiographic estimation of the myocardial area at risk, although this approach has not been well validated. Technetium-99m sestamibi is a perfusion imaging agent with little redistribution after initial myocardial uptake. This characteristic allows for injection during angioplasty and later imaging for visualization and quantitation of the nonperfused area at risk. METHODS: Thirty-nine patients referred for coronary angioplasty were studied. Technetium-99m sestamibi was injected intravenously during angioplasty balloon inflation. Planar (33 patients) or tomographic (6 patients) imaging was performed after completion of angioplasty. Imaging was repeated 24 to 48 h later. Myocardial risk area (perfusion defect on angioplasty image) was quantified as an integral using circumferential count distribution profiles and normal reference. Angiographic risk area was assessed using five scoring methods. RESULTS: The scintigraphic risk area was 14 +/- 15 on planar images and 39 +/- 16 on tomography. Scintigraphic risk area of patients with infarction was larger than in patients without (22 +/- 17 versus 7 +/- 8, p = 0.003). The left anterior descending coronary artery had a larger mean risk area than other vessels (22 +/- 15 versus 7 +/- 11, p = 0.002). The presence of angiographic collateral channels was associated with smaller risk areas. Angiographic risk scores correlated only moderately with the technetium-99m sestamibi risk area (r = 0.54 to 0.65), with considerable spread of data. CONCLUSIONS: Area at risk estimated from coronary angiography does not correlate well with that from quantitative myocardial perfusion imaging with technetium-99m sestamibi. These findings emphasize that the functional significance of coronary artery disease is not predicted by coronary anatomy alone.

Fate of lesion-related side branches after coronary artery stenting.

OBJECTIVES: The aim of this study was to assess the immediate and long-term patency of lesion-associated side branches after coronary artery stenting. BACKGROUND: The possible adverse effects related to implantation of coronary stents are not completely known. An important potential complication of stenting is side branch occlusion due to mechanical obstruction or thrombosis. METHODS: Serial coronary angiography was performed in 153 patients (167 lesions) at baseline, after conventional balloon angioplasty, immediately after Palmaz-Schatz stent placement and at 6 months. The patency of side branches, where present, was analyzed at each of these points. RESULTS: Of 167 lesions stented, 57 stent placements spanned 66 side branches with a diameter > or = 1 mm. Twenty-seven (41%) of these side branches had > or = 50% ostial stenosis before standard balloon angioplasty. Six side branches became occluded after standard balloon angioplasty and remained occluded after stenting. Of the 60 side branches patent after conventional angioplasty, 57 (95%) remained patent immediately after stenting. All three side branches that became occluded after stenting had > or = 50% ostial stenosis at baseline. All 60 side branches, including the 3 initially occluded after stenting, were patent at 6-month follow-up. CONCLUSIONS: These findings demonstrate that 1) acute side branch occlusion due to coronary stenting occurs infrequently; 2) when side branch occlusion occurs, it is associated with intrinsic ostial disease; and 3) the patency of side branch ostia is well maintained at long-term follow-up.

Effect of intracoronary stenting on intimal dissection after balloon angioplasty: results of quantitative and qualitative coronary analysis.

The effect of the Palmaz-Schatz stent on the angiographic appearance and residual luminal stenosis in patients with intimal dissection after balloon angioplasty was evaluated in 84 consecutive patients (90 lesions). Coronary angiography was performed before angioplasty, after conventional angioplasty and after stent implantation. The degree of intimal disruption was assessed as follows: grade 0, no dissection; grade 1, simple dissection (intraluminal linear defect or extraluminal cap extravasation); or grade 2, complex dissection (nonlinear spiral defect or luminal defect with multiple irregular borders). Quantitative coronary analysis of digitized cineangiograms was performed with use of a computerized automatic edge detection algorithm. After balloon angioplasty, 31 (34%) of 90 lesions demonstrated intimal dissection (18 simple, 13 complex). After stent implantation, intimal dissection improved by greater than or equal to 1 grade in 29 (94%) of the 31 lesions with 27 (87%) reduced to grade 0 (that is, no dissection). Dissection grade improved after stenting in 16 (89%) of 18 simple dissections and in all 13 complex dissections. Mean diameter stenosis was 77 +/- 17% before angioplasty, 47 +/- 17% after angioplasty and 14 +/- 10% after stenting (before angioplasty vs. after angioplasty and after angioplasty vs. after stenting, p less than 0.0001). In conclusion, intracoronary stenting is effective in reducing the residual luminal stenosis and in improving the angiographic appearance of intimal dissections after conventional balloon angioplasty.

Immediate results and late outcomes after stent implantation in saphenous vein graft lesions: the multicenter U.S. Palmaz-Schatz stent experience. The Palmaz-Schatz Stent Study Group.

OBJECTIVES: This study reports the multicenter registry experience evaluating the safety and efficacy of the Palmaz-Schatz stent in the treatment of saphenous vein graft disease. BACKGROUND: Saphenous vein graft angioplasty is associated with frequent periprocedural complications and a high frequency of restenosis. Stent implantation has been shown to reduce restenosis, with improved long-term outcomes in the treatment of native coronary artery disease. Preliminary experience with stent placement in the treatment of saphenous vein graft lesions has been favorable. METHODS: Twenty U.S. investigator sites enrolled a total of 589 symptomatic patients (624 lesions) for treatment of focal vein graft stenoses between January 1990 and April 1992. Follow-up angiography was performed at 6 months, and the clinical course of all study patients was prospectively collected at regular intervals for up to 12 months. RESULTS: Stent delivery was successful in 98.8% of cases, and the procedural success rate was 97.1%. The lesion diameter stenosis decreased from 82 +/- 12% (mean +/- SD) before to 6.6 +/- 10.2% after treatment. Major in-hospital complications occurred in 17 patients (2.9%); stent thrombosis was found in 8 (1.4%); and major vascular or bleeding complications were noted in 83 (14.3%). Six-month angiographic follow-up revealed an overall restenosis rate (> or = 50% diameter stenosis) of 29.7%. Multivariate logistic regression analysis indicated that 1) restenotic lesions, 2) smaller reference vessel size, 3) history of diabetes mellitus, and 4) higher percent poststent diameter stenosis were independent predictors of restenosis. The 12-month actuarial event-free survival was 76.3%. CONCLUSIONS: Stent implantation in patients with focal saphenous vein graft lesions can be achieved with a high rate of procedural success, acceptable major complications, reduced angiographic restenosis and favorable late clinical outcome compared with historical balloon angioplasty control series. The rigorous anticoagulation regimen after stent placement results in more frequent vascular and other bleeding complications. Future randomized studies comparing standard balloon angioplasty with stent implantation are warranted to properly assess the full impact of stent placement in the treatment of saphenous vein graft lesions.

Long-term angiographic and clinical outcome after implantation of a balloon-expandable stent in the native coronary circulation. Palmaz-Schatz Stent Study Group.

OBJECTIVES: The purpose of this study was to examine the long-term clinical and angiographic outcome after coronary stent implantation. BACKGROUND: Previous reports have shown a discordance between the excellent initial angiographic results and subsequent adverse clinical events after coronary artery stenting. METHODS: Single Palmaz-Schatz stents were electively implanted in the native coronary arteries of 300 consecutive patients. Angiograms were obtained at baseline, after balloon angioplasty, after stent implantation and at 6 months after implantation. Films were analyzed by a panel of angiographers utilizing an automated edge detection program. Clinical events, including death, myocardial infarction, coronary bypass surgery and repeat angioplasty, were recorded for 1 year. RESULTS: Although there were no acute in laboratory vessel closures, stent thrombosis occurred in 14 patients (4.7%) at a mean +/- SD of 5 +/- 3 days after implantation. Two hundred fifty-eight (90%) of 286 eligible patients had follow-up angiography at 6.1 +/- 2.2 months after stent implantation. Minimal lumen diameter increased from 0.80 +/- 0.39 mm at baseline to 1.65 +/- 0.51 mm after angioplasty and further increased to 2.55 +/- 0.49 mm after stent placement (p = 0.0001). At follow-up there was a 0.85-mm late loss in lumen diameter, with a final minimal lumen diameter at 6 months of 1.70 +/- 0.71 mm. Restenosis, defined as > or = 50% diameter stenosis at follow-up, occurred in 14% of patients with previously untreated lesions and in 39% of patients with previous angioplasty (p < 0.001). Clinical events after 1 year for the entire group of 300 patients included death in 0.7%, myocardial infarction in 3.7%, bypass grafting in 8% and repeat angioplasty in 13%. Freedom from any adverse clinical event was 80% for all treated patients and 87% for those with previously untreated lesions. CONCLUSIONS: Elective use of this balloon-expandable stent in the native coronary circulation is associated with a low restenosis rate by quantitative angiography in previously untreated lesions and a favorable clinical outcome with an excellent event-free survival rate at 1 year.

Modulation of circulating cellular adhesion molecules in postmenopausal women with coronary artery disease.

OBJECTIVES: The present study examined the association of estrogen (E2) and the inflammatory response of endothelium in coronary artery disease (CAD) by measuring circulating cellular adhesion molecules (cCAMs) in subjects with atherosclerosis. BACKGROUND: Atherosclerotic plaque demonstrates features similar to inflammation. Endothelial cell activation by inflammatory cytokines induces expression of cellular adhesion molecules (CAMs), thereby perhaps augmenting leukocyte adhesion and recruitment and subsequent development of atherosclerosis. The incidence of CAD is lower in women; this may be due to the cardioprotective effects of E2. METHODS: Consecutive eligible subjects with CAD admitted for cardiac catheterization were studied. The groups evaluated were men, postmenopausal women receiving E2 replacement therapy (ERT), postmenopausal women not receiving ERT and premenopausal women. Control groups included men and women without CAD. Preprocedural blood samples were drawn from all groups. Measurements of cCAMs, E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 were performed by enzyme-linked immunoabsorbant assay. E2 levels were assessed by radioimmunoassay. RESULTS: We observed a statistically significant increase in all cCAMs in men with CAD and postmenopausal women with CAD not receiving ERT compared with postmenopausal women with CAD receiving ERT. Premenopausal women with CAD and postmenopausal women with CAD receiving ERT had a significant increase in VCAM-1 alone compared with the female control group. CONCLUSIONS: A possible mechanism by which E2 exerts one of its cardioprotective effects is by limiting the inflammatory response to injury by modulating the expression of CAMs from the endothelium.

Insulin degradation in serum of a patient with apparent insulin resistance.

A case is presented of a thin diabetic male who was resistant to large doses of sc and im insulin but responded to small dose of insulin given iv. His serum contained an enzyme that degraded [125I]insulin in vitro. We postulate that his apparent insulin resistance was due to inactivation of insulin at the injection site. We propose that the sera of patients with insulin resistance be tested for [125I]insulin-degrading activity as a possible means of identifying patients with this syndrome.

Dynamics of early and late left ventricular filling determined by Doppler two-dimensional echocardiography during percutaneous transluminal coronary angioplasty.

To study the influence of ischemia on both early and late left ventricular filling, Doppler 2-dimensional echocardiography was used to measure filling parameters during percutaneous transluminal coronary angioplasty (PTCA) in 26 patients. Doppler recordings were taken immediately before balloon inflation and continuously during balloon inflation and deflation until 60 seconds into the recovery period. During PTCA of the left anterior descending artery (16 patients) there was a 35% decrease in early peak filling rate from 269 +/- 88 to 169 +/- 55 ml/s (p less than 0.0005) by 60 seconds of balloon inflation. In patients undergoing PTCA of the left circumflex (4 patients) or dominant right coronary artery (6 patients), the early peak filling rate decreased 15% from 325 +/- 126 to 284 +/- 137 ml/s (p less than 0.005). The decrease in early peak filling rate became evident at approximately 15 seconds after balloon inflation and fully recovered 20 seconds after balloon deflation. Rather than an expected increase in atrial stroke volume and a decrease in early to late filling ratio during coronary occlusion, there was a 28% decrease in atrial stroke volume during left anterior descending coronary artery PTCA and a 6% decrease during right coronary and circumflex PTCA. Because of the simultaneous decrease in both early and late ventricular filling, peak early to late filling ratio was only slightly altered during PTCA. There was an 83% increase in mean pulmonary artery wedge pressure during balloon inflation from 12 +/- 5 to 20 +/- 4 mm Hg. In 11 of these patients global systolic function was measured on subsequent inflations during PTCA using 2-dimensional echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation of continuous radionuclide left ventricular functioning monitoring in detecting silent myocardial ischemia during balloon angioplasty of the left anterior descending coronary artery.

Silent myocardial ischemia has been inferred from transient ST-segment depression during continuous electrocardiographic monitoring. Recently, continuous ambulatory monitoring of left ventricular (LV) function using a radionuclide technique (VEST) has demonstrated episodes of significant silent LV dysfunction in the absence of electrocardiographic changes. To validate the demonstration of silent LV dysfunction with this technique, 12 men were studied during percutaneous transluminal coronary angioplasty. A total of 18 left anterior descending coronary artery balloon inflations were performed. Balloon inflations at 8 +/- 2 atm (4 to 10 atm) lasted 70 +/- 16 seconds. Seventeen of 18 inflations were associated with a decrease in LV ejection fraction greater than 0.10. Mean LV ejection fraction decreased from 0.53 +/- 0.08 to 0.28 +/- 0.11 (p less than 0.0001). In contrast, there was pain in only 10 inflations and ST-segment changes in 7. LV dysfunction was associated with a minimal increase in end-diastolic volume (4 +/- 3%, p less than 0.003), and a major increase in relative end-systolic volume (69 +/- 43%, p less than 0.001). These data suggest that continuous monitoring of LV function with the VEST can sensitively detect silent ischemic decreases in LV function occurring during angioplasty, and provide further validation of the use of this technique for detecting silent myocardial ischemia.

Predictors of success in percutaneous transluminal coronary angioplasty of chronic total occlusions.

Earlier studies have indicated that percutaneous transluminal coronary angioplasty (PTCA) of chronic total occlusions has a low success rate. To determine success rate and assess clinical and angiographic variables associated with success and complications, 57 total occlusions in 56 patients undergoing PTCA were analyzed. The clinical duration of occlusion was 51 +/- 86 days. Success (less than 50% residual stenosis) was achieved at 40 of 57 (70%) dilatation sites. Of these 57 total occlusions, 5 were attempted within 24 hours of acute myocardial infarction, 35 between 1 day and 8 weeks of clinical occlusion, 13 greater than 8 weeks and 4 were of unknown duration. Success rates were 4 of 5, 25 of 35, 9 of 13 and 2 of 4, respectively, in each group (difference not significant, comparison of all time groups). Of the 9 narrowings with a successful PTCA for an occlusion greater than 8 weeks, the mean duration of occlusion was 93 +/- 41 days (range 60 to 180). None of the attempted dilatations of occlusions with a clinical duration of greater than 180 days (n = 3) was successful. None of the clinical or angiographic variables (including tortuosity, length of occlusion gap, distance of the occlusion from the vessel origin, thrombus, lesion calcium, collaterals, prior myocardial infarction, vessel dilated or diffuse disease) impacted on success rate (difference not significant for all). No patient died, had a Q-wave infarction, required emergency coronary artery bypass grafting or underwent repeat PTCA within 7 days of the procedure. Non-Q-wave infarction occurred in 2 of 56 patients (4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of myocardial ischemia during percutaneous transluminal coronary angioplasty with oxygenated Fluosol.

The effects of perfusion of an oxygen-carrying perfluorochemical emulsion (Fluosol) in alleviating symptoms of myocardial ischemia during balloon occlusion were examined in a multicenter trial of 245 patients. Severe anginal pain occurred less frequently in patients receiving Fluosol perfusion (21%) than in those receiving routine angioplasty (34%) (p less than 0.05). ST-segment changes at balloon deflation in routine angioplasty patients were significantly greater than in patients who received oxygenated Fluosol perfusion (2.2 +/- 1.2 vs 1.7 +/- 0.9 mm; p less than 0.03). Profound regional wall dysfunction (-561 +/- 224 U) was observed in routine angioplasty patients by 2-dimensional echocardiography. Patients receiving oxygenated Fluosol perfusion, however, maintained near baseline levels of ventricular function (-61 +/- 335 U) during occlusion (p less than 0.0001). Mean global left ventricular ejection fraction was preserved at baseline levels during balloon inflation in patients perfused with oxygenated Fluosol but decreased significantly (p less than 0.001) during occlusion in routine angioplasty patients. A total of 26 complications (19 routine group; 7 perfusion group) was reported. Adverse responses to the perfusate were infrequent, occurring in 1.6 and 2.0% of patients after the test dose and during perfusion, respectively. Thus, transcatheter perfusion with an oxygen-carrying perfluorochemical emulsion is effective in alleviating myocardial ischemia during angioplasty and can be safely administered in this patient population.

High-speed rotational atherectomy of human coronary stenoses: acute and one-year outcomes from the New Approaches to Coronary Intervention (NACI) registry.

High-speed rotational atherectomy (RA) is a new percutaneous procedure for treatment of coronary stenoses that operates by the unique mechanism of plaque abrasion. This article reports acute (in-hospital) outcomes and 1-year follow-up in a large cohort of patients treated with this device by NACI investigators. A total of 525 patients with 670 lesions treated with RA form the substrate of this report. Patients tended to be older (mean age 64.8 years) than those in previously reported series of percutaneous transluminal coronary angioplasty (PTCA), with more extensive disease and more complex lesions. Calcification was present in 54% of lesions, and eccentricity in 41%. Balloon angioplasty postdilation was performed after RA in 88% of cases. Angiographic and procedural success (angiographic success without death, Q-wave myocardial infarction [MI] or emergency coronary artery bypass graft [CABG] surgery) rates were 89% and 88%, respectively. Acute in-hospital events included 4 deaths (1%) and 1 emergency CABG surgery (0.4%). MI occurred in 6% of patients, consisting predominantly of non-Q-wave MI (5%). After RA, angiographic complications included coronary dissection (12%), abrupt closure (5%), side branch occlusion (3%), and distal embolization (3%). Most of these were resolved after postdilation except for coronary dissection, which was present in 15% of lesions treated. Mean length of stay was 3 days. At 1-year follow-up, 27% of patients required target lesion revascularization and 30% had experienced death, Q-wave MI, or target lesion revascularization. Preprocedural characteristics that independently predicted 1-year death, Q-wave MI, or target lesion revascularization were male gender, high risk for surgery, target lesions that were proximal to or in bifurcations, eccentric, long, or highly stenosed. RA, even when applied to lesions of traditionally unfavorable morphology, appears to provide reasonable procedural and angiographic success rates. Restenosis and progression of disease contribute to subsequent clinical and procedural events.

Acute and long-term outcome after Palmaz-Schatz stenting: analysis from the New Approaches to Coronary Intervention (NACI) registry.

The randomized Stent Restenosis Study (STRESS) and Belgium Netherlands Stent (Benestent) trials established that elective use of Palmaz-Schatz stents (PSSs) in native coronary arteries with de novo lesions is associated with increased procedural success and reduced restenosis. However there are other clinical indications for which stents are commonly used (unplanned use, vein grafts, restenosis lesions) that are not addressed in these studies. From 1990-1992, 688 lesions in 628 patients were treated with PSSs in the New Approaches to Coronary Intervention (NACI) registry. Angiographic core laboratory readings were available for 543 patients (595 lesions, of which 106 were stented for unplanned indications, 239 were in saphenous vein bypass grafts, and 296 were previously treated). The cohort of patients in whom stents were placed for unplanned indications had more women, current smokers, and had a higher incidence of recent myocardial infarction (MI). Patients who underwent stenting of saphenous vein grafts were older, had a higher incidence of diabetes mellitus, unstable angina, prior MI, and congestive heart failure. Lesion success was similar in all cohorts (98%), but procedural success was significantly higher for planned stenting (96% vs 87%; p < 0.01). Predictors of adverse events in-hospital were presence of a significant left main stenosis and stenting for unplanned indication. The incidence of target lesion revascularization by 30 days was significantly higher for patients undergoing unplanned stenting due to a higher risk for stent thrombosis. Recent MI, stenting in native lesion, and small postprocedural minimum lumen diameter independently predicted target lesion revascularization at 30 days. Independent predictors of death, Q-wave myocardial infarction, or target lesion revascularization at 1 year included severe concomitant disease, high risk for surgery, left main disease, stenting in the left main coronary artery, and low postprocedure minimum lumen diameter.

Pulmonary and pleural complications of cardiac disease.

Disorders of the heart frequently cause pulmonary dysfunction because of the close structural and functional association of the heart and lungs. The pulmonary vasculature is very commonly affected by cardiac pathology. The pulmonary vasculature is normally a low-pressure, low-resistance circuit with high compliance and tremendous vascular reserve. Although resting vascular tone is low, there are many identified mediators of pulmonary arterial tone that may help mediate pulmonary blood flow. Alveolar hypoxia is clearly a stimulus for increasing pulmonary vascular resistance although factors that mediate the response to hypoxia are not fully understood. Patients with left-to-right shunting due to congenital heart disease because of elevations in pulmonary artery flow and pressure tend to develop progressive anatomic changes in the pulmonary vasculature. This leads to an increase in pulmonary vascular resistance, irreversible pulmonary hypertension, right heart failure, reversal of shunt flow, and Eisenmenger's syndrome. The degree of anatomic vascular damage due to left-to-right shunting can be graded histologically. Lesser grades of damage are reversible with corrective surgery, whereas more severe grades show no improvement or progression with operation. Chronic left-sided congestive heart failure seen in rheumatic mitral stenosis can cause secondary changes in the pulmonary vasculature. Pulmonary hypertension and increased pulmonary vascular resistance can increase reflexly and form a "second stenosis" that further limits cardiac output. Unlike congenital heart disease, severe grades of pulmonary arterial damage are not seen in left heart failure from mitral stenosis or other causes, and consequently with surgical correction pulmonary hypertension reverses. Pulmonary function testing is adversely affected by congestive heart failure. Both restrictive (stiff lungs) and obstructive (cardiac asthma) defects are observed in congestive heart failure. DLCO is abnormally decreased. With treatment of heart failure these defects reverse. Both elevated systemic and pulmonary venous pressures affect fluid filtration in the pleural space and cause pleural fluid accumulation. The fluid is transudative with low protein, low lactate dehydrogenase, and low cell counts. Transudative effusions from heart failure resolve with treatment. With large effusions and cardiomegaly, pulmonary dysfunction results because of atelectasis from compression and space-occupying effects of the heart and pleural fluid. Following myocardial infarction, cardiac surgery, or other cardiac trauma, the postcardiac injury syndrome can result. The syndrome is characterized by exudative pleural and pericardial effusions along with pulmonary infiltrates, fever, chest pain, leukocytosis, and an elevated ESR. The syndrome must be diagnosed by exclusion of bacterial pneumonia, pulmonary emboli, and congestive heart failure. Treatment is with nonsteroidal anti-inflammatory agents or systemic co

Percutaneous transluminal coronary angioplasty during acute myocardial infarction.

Intravenous thrombolytic therapy with streptokinase in the setting of acute MI has been shown to be effective in improving left ventricular function, limiting infarct size, and improving early mortality. The benefit of this therapy is greatest when administered within 3 hours and is of minimal benefit when given more than 6 hours from symptom onset. Newer second generation thrombolytic agents such as intravenous r-TPA have been shown to be more effective at establishing patency of acutely thrombosed coronary arteries. TPA treatment produces patency rates similar to those observed with intracoronary administration of streptokinase (65 to 75 per cent). This agent will probably become standard therapy for patients with acute MI. Unfortunately, there are significant problems with systemic thrombolytic therapy. The potential for bleeding complications contraindicates the use of this therapy in patients with recent cerebrovascular events, recent surgery, or other possible bleeding problems. Acute angioplasty of the infarct-related artery has been shown to be effective in restoring blood flow in 85 per cent of patients with acute MI. Preliminary studies have suggested that this therapy, when administered within 4 hours from symptom onset, improves global and regional left ventricular function to a greater degree than intracoronary streptokinase. Patients receiving acute PTCA as a primary reperfusion modality have a lower incidence of post-infarction angina and provokable ischemia by exercise testing. If facilities and skilled personnel are available to perform PTCA within 4 hours from symptom onset, this therapy remains an alternative revascularization modality in patients with acute infarction and contraindications to systemic thrombolytic therapy. However, the benefit of PTCA with regard to reduction in mortality when used in this manner is unproven. PTCA can also be used as an adjunctive therapy administered at some time following systemic thrombolytic therapy. Performing PTCA acutely offers the potential to restore blood flow in 90 per cent of the patients that initially fail thrombolytic therapy. However, despite the use of PTCA in this subgroup, benefits with regard to improved ventricular function and decreased mortality have yet to be conclusively demonstrated. Performing acute PTCA following systemic thrombolytic therapy also incurs a high incidence of bleeding complications. If initial thrombolytic therapy reestablishes vessel patency, similar improvements in ventricular function can be expected even if PTCA is deferred until clinically indicated by evidence of recurrent ischemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Update on percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty was first performed in a human coronary artery in 1977. In this article, we review the possible mechanisms of angioplasty, current indications for angioplasty, and complications of angioplasty including acute closure and restenosis.

Myocardial protection during percutaneous transluminal coronary angioplasty.

Coronary angioplasty results in transient coronary artery occlusion. This article reviews with systemic and regional methods aimed at preventing the electrophysiologic and hemodynamic consequences of regional myocardial ischemia.

The right ventricle in disorders causing pulmonary venous hypertension.

The right ventricle is frequently affected by pulmonary arterial hypertension of postcapillary obstructive origin. The disorders that cause states of pulmonary venous hypertension arise in the left ventricle, left atrium, or pulmonary veins. Biochemical factors, the pericardium, interventricular septum, and pulmonary arterial system combine to communicate the effects of these disorders to the right ventricle. Although not ideally suited to pressure loading, the right ventricle undergoes a series of structural and hemodynamic adaptations that allow for chronic compensation until failure supervenes, with characteristic clinical findings. Exercise may serve to magnify the abnormalities of right ventricular function. Correction of left-sided heart lesions with improvement in pulmonary venous hypertension is associated with favorable effects on the right ventricle. In states of left-sided heart failure, the level of right ventricular function may provide important prognostic information.