Use of Mechanical Circulatory Support in Chronic Total Occlusion Percutaneous Coronary Intervention

The use of mechanical circulatory support (MCS) in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study. We analyzed the clinical and angiographic characteristics, and procedural outcomes of 7,171 CTO PCIs performed between 2012 and 2021 at 35 international centers. Mean age was 64.5 ± 10 years, mean left ventricular ejection fraction was 50 ± 13%. MCS was used in 4.5%, prophylactically in 78.7%, and urgently in 21.3%. The most common type of MCS overall was Impella CP (Abiomed) (55.5%), followed by intra-aortic balloon pump (14.8%) and TandemHeart (LivaNova Inc.) (10.0%). Prophylactic MCS patients were more likely to have diabetes mellitus (55% vs 42%, p <0.001) and had more complex lesions compared with cases without prophylactic MCS (Japan-CTO score: 2.80 ± 1.22 vs 2.39 ± 1.27, p <0.001). Cases with prophylactic MCS had similar technical (86% vs 87%, p = 0.643) but lower procedural (80% vs 86%, p = 0.028) success rates and higher rates of periprocedural major cardiac adverse events compared with no prophylactic MCS use (6.55% vs 1.68%, p <0.001). Urgent MCS use was associated with lower technical (68% vs 87%, p <0.001) and procedural (39% vs 86%, p <0.001) success rates and higher major cardiac adverse events compared with no-MCS use (32.26% vs 1.68%, p <0.001). The differences persisted in multivariable analyses. In summary, in this contemporary multicenter registry, MCS was used in 4.5% of CTO PCIs, mostly prophylactically (78.7%). Elective MCS cases had similar technical success but a higher risk of complications. Urgent MCS cases had lower technical and procedural success and higher periprocedural major complication rates.

Combined Coronary Orbital Atherectomy and Intravascular Lithotripsy for the Treatment of Severely Calcified Coronary Stenoses: The First Case Series

OBJECTIVE

Severely calcified coronary stenoses remain a significant challenge during contemporary percutaneous coronary intervention (PCI), often requiring advanced therapies to circumvent suboptimal lesion preparation and major adverse cardiac events (MACEs). Recent reports suggest combined coronary atherectomy and intravascular lithotripsy (IVL) may achieve superior preparation of severely calcified coronary stenoses during PCI. We sought to evaluate the safety and utility of combined orbital atherectomy (OA) and IVL for the modification of coronary artery calcification (CAC) prior to drug-eluting stent (DES) implantation in PCI.

METHODS

We performed a retrospective review of all patients who underwent coronary OA and IVL within a single PCI procedure at our institution. The primary outcome was procedural success, defined as successful DES implantation with a residual percent diameter stenosis of <30% and Thrombolysis in Myocardial Infarction (TIMI) 3 flow following PCI without occurrence of in-hospital MACE (cardiac death, myocardial infarction, or target-vessel revascularization). MACE was additionally assessed at 30 days post intervention.

RESULTS

Eight patients underwent combined coronary OA and IVL within a single PCI procedure. The mean percent diameter stenosis prior to intervention was 80.5 ± 8.3%, with a mean calcific arc of 338 ± 42°. Procedural success was achieved in 7 of 8 cases (87.5%). Both in-hospital and 30-day MACE rates were 0%.

CONCLUSION

We report the safe and effective use of combined coronary OA and IVL for the preparation of severely calcified coronary stenoses during PCI. Through their distinct yet complementary mechanisms of action, the combined use of these therapies may achieve superior preparation of severely calcified coronary stenoses during PCI.

Intermittent Occlusion of the Superior Vena Cava to Improve Hemodynamics in Patients With Acutely Decompensated Heart Failure: The VENUS-HF Early Feasibility Study

BACKGROUND

Reducing congestion remains a primary target of therapy for acutely decompensated heart failure. The VENUS-HF EFS (VENUS-Heart Failure Early Feasibility Study) is the first clinical trial testing intermittent occlusion of the superior vena cava with the preCARDIA system, a catheter mounted balloon and pump console, to improve decongestion in acutely decompensated heart failure.

METHODS

In a multicenter, prospective, single-arm exploratory safety and feasibility trial, 30 patients with acutely decompensated heart failure were assigned to preCARDIA therapy for 12 or 24 hours. The primary safety outcome was a composite of major adverse cardiovascular and cerebrovascular events through 30 days. Secondary end points included technical success defined as successful preCARDIA placement, treatment, and removal and reduction in right atrial and pulmonary capillary wedge pressure. Other efficacy measures included urine output and patient-reported symptoms.

RESULTS

Thirty patients were enrolled and assigned to receive the preCARDIA system. Freedom from device- or procedure-related major adverse events was observed in 100% (n=30/30) of patients. The system was successfully placed, activated and removed after 12 (n=6) or 24 hours (n=23) in 97% (n=29/30) of patients. Compared with baseline values, right atrial pressure decreased by 34% (17±4 versus 11±5 mm Hg, P<0.001) and pulmonary capillary wedge pressure decreased by 27% (31±8 versus 22±9 mm Hg, P<0.001). Compared with pretreatment values, urine output and net fluid balance increased by 130% and 156%, respectively, with up to 24 hours of treatment (P<0.01).

CONCLUSIONS

We report the first-in-human experience of intermittent superior vena cava occlusion using the preCARDIA system to reduce congestion in acutely decompensated heart failure. PreCARDIA treatment for up to 24 hours was well tolerated without device- or procedure-related serious or major adverse events and associated with reduced filling pressures and increased urine output. These results support future studies characterizing the clinical utility of the preCARDIA system.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03836079.

The Utility of Peripheral Intravascular Lithotripsy in Calcific Coronary Artery Disease: A Case Series

BACKGROUND

Coronary intravascular lithotripsy (IVL) is an emerging therapy for the modification of coronary artery calcification (CAC). Data on its use in several clinical and lesion subsets are limited due to their exclusion from preapproval trials.

METHODS

We performed a retrospective review of patients who were excluded from preapproval trials of coronary IVL and underwent CAC modification with the off-label use of a peripheral IVL system. The primary outcome was a composite of procedural success, defined as residual stenosis <10%, and no major adverse cardiac event (MACE), ie, cardiac death, myocardial infarction, or target- vessel revascularization, in hospital and at 30 days.

RESULTS

Between June 2019 and April 2020, a total of 9 patients who underwent off-label coronary IVL were identified. Exclusion criteria from preapproval trials included a target lesion within an unprotected left main coronary artery (ULMCA; n = 3) and/or ostial location (n = 5), a target lesion involving in-stent restenosis (n = 3), a second target-vessel lesion with >50% stenosis (n = 1), and/or New York Heart Association class III/IV heart failure (n = 5). The primary outcome was achieved in 8 patients. MACE rate was 0% in hospital and at 30 days. For ULMCA lesions (n = 3), residual stenosis was 0% in 2 patients and 10% in 1 patient. For right coronary artery lesions (n = 3), residual stenosis was 0% in 2 patients and 40% in 1 patient. For left anterior descending coronary artery lesions (n = 3), residual stenosis was 0% in all patients.

CONCLUSION

Coronary IVL with a peripheral IVL system may be an effective therapy for CAC modification within ULMCA disease, ostial disease, in-stent restenosis, and New York Heart Association class III/IV heart failure.

Fulminant myocarditis in a patient with coronavirus disease 2019 and rapid myocardial recovery following treatment

Coronavirus disease 2019 (COVID‐19) is a global pandemic increasingly encountered in the clinical setting. It typically manifests as a respiratory illness, although cardiac involvement is common and portends a worse prognosis. We present the case of a 56‐year‐old male admitted with COVID‐19 fulminant myocarditis and cardiogenic shock. We discuss important aspects of the multidisciplinary and interventional care involved in treating cardiogenic shock as well as the likely mechanisms of, and potential treatment for, COVID‐19 myocarditis. The various pathways of myocardial injury, including direct viral damage, macrophage activation, and lymphocytic infiltration, are outlined in detail in addition to associated pathology such as cytokine release syndrome. COVID‐19 is a complex and multisystem disease process; in addition to supportive care, specific consideration should be given to the underlying mechanism of injury for each patient.

Catheter-based embolectomy prior to right ventricular mechanical circulatory support placement after heart transplantation

Severe acute isolated right ventricular failure has limited dedicated percutaneous temporary mechanical circulatory support options, especially after orthotopic heart transplantation. The advent of the Impella RP device provides a newer option, though an absolute contraindication to device placement is thrombus within the right heart. We present a novel case where catheter-based embolectomy was used to evacuate right heart thrombus before Impella RP placement in a patient with severe acute right ventricular failure due to primary graft dysfunction after orthotopic heart transplantation.

Extracellular volume fraction is more closely associated with altered regional left ventricular velocities than left ventricular ejection fraction in nonischemic cardiomyopathy

BACKGROUND

Nonischemic cardiomyopathy is a common cause of left ventricular (LV) dysfunction and myocardial fibrosis. The purpose of this study was to noninvasively evaluate changes in segmental LV extracellular volume (ECV) fraction, LV velocities, myocardial scar, and wall motion in nonischemic cardiomyopathy patients.

METHODS AND RESULTS

Cardiac MRI including pre- and postcontrast myocardial T1 mapping and velocity quantification (tissue phase mapping) of the LV (basal, midventricular, and apical short axis) was applied in 31 patients with nonischemic cardiomyopathy (50±18 years). Analysis based on the 16-segment American Heart Association model was used to evaluate the segmental distribution of ECV, peak systolic and diastolic myocardial velocities, scar determined by late gadolinium enhancement, and wall motion abnormalities. LV segments with scar or impaired wall motion were significantly associated with elevated ECV (rs =0.26; P<0.001) and reduced peak systolic radial velocities (r=-0.43; P<0.001). Regional myocardial velocities and ECV were similar for patients with reduced (n=12; ECV=0.28±0.06) and preserved left ventricular ejection fraction (n=19; ECV=0.30±0.09). Patients with preserved left ventricular ejection fraction showed significant relationships between increasing ECV and reduced systolic (r=-0.19; r=-0.30) and diastolic (r=0.34; r=0.26) radial and long-axis peak velocities (P<0.001). Even after excluding myocardial segments with late gadolinium enhancement, significant relationships between ECV and segmental LV velocities were maintained indicating the potential of elevated ECV to identify regional diffuse fibrosis not visible by late gadolinium enhancement, which was associated with impaired regional LV function.

CONCLUSIONS

Regionally elevated ECV negatively affected myocardial velocities. The association of elevated regional ECV with reduced myocardial velocities independent of left ventricular ejection fraction suggests a structure-function relationship between altered ECV and segmental myocardial function in nonischemic cardiomyopathy.

Eptifibatide-induced thrombocytopenia: with thrombosis and disseminated intravascular coagulation immediately after left main coronary artery percutaneous coronary angioplasty

Early clinical trials of eptifibatide did not show a significant association between eptifibatide and the development of thrombocytopenia, thrombosis, or disseminated intravascular coagulation. However, more recent literature has suggested a significant association between eptifibatide and the development of thrombocytopenia and thrombosis. Although the true incidence and the pathophysiology of these associations are unknown, the development of these events can be life-threatening. Herein, we describe the case of a patient who experienced acute onset of profound thrombocytopenia, developing thrombosis, pulmonary emboli, and disseminated intravascular coagulation. This paper adds to the few previous reports of cases that suggested an association between thrombocytopenia, thrombosis, and the administration of eptifibatide. To the best of our knowledge, this is the first case report in the medical literature that associates the new onset of thrombocytopenia, thrombosis, and disseminated intravascular coagulation with the administration of eptifibatide. We also provide a subject review.

Outcomes and complications associated with off-label and untested use of drug-eluting stents

CONTEXT

Limited data exist regarding use of drug-eluting stents outside of approved indications in real-world settings.

OBJECTIVES

To determine the frequency, safety, and effectiveness of drug-eluting stents for off-label (restenosis, bypass graft lesion, long lesions, vessel size outside of information for use recommendation) and untested (left main, ostial, bifurcation, or total occlusion lesions) indications in percutaneous coronary intervention (PCI).

DESIGN, SETTING, AND PATIENTS

Observational, prospective, multicenter registry to evaluate in-hospital, 30-day, and 1-year outcomes among patients undergoing PCI between January and June 2005 in 140 US academic and community medical centers. Of 7752 PCI-treated patients, 6993 (90%) received drug-eluting stents; of these, 5851 (84%) received no other devices. Standard, off-label, and untested use was determined in 5541 (95%) of these 5851 patients, constituting the study cohort.

MAIN OUTCOME MEASURES

Frequency of off-label and untested use, 1-year repeat target vessel revascularization, and composite of death, myocardial infarction (MI), or stent thrombosis at in-hospital follow-up and during 1 year of follow-up.

RESULTS

Of 5541 patients receiving drug-eluting stents, 2588 (47%) received stents for off-label or untested indications. Adjusted in-hospital risk of death, MI, or stent thrombosis was not statistically different with off-label or untested vs standard use. At 30 days, the risk of this composite end point was significantly higher with off-label use (adjusted hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.24-3.48; P = .005) but not untested use (adjusted HR, 1.45; 95% CI, 0.79-2.67; P = .23). Excluding early events, this end point was not different at 1 year with off-label use (adjusted HR, 1.10; 95% CI, 0.79-1.54; P = .57) or untested use (adjusted HR, 0.91; 95% CI, 0.60-1.38; P = .66). At 1 year, compared with standard use, significantly higher rates of target vessel revascularization were associated with off-label use (adjusted HR, 1.49; 95% CI, 1.13-1.98; P = .005) and untested use (adjusted HR, 1.49; 95% CI, 1.10-2.02; P = .01), although absolute rates were low (standard, 4.4% [n = 113]; off-label, 7.6% [n = 95]; untested, 6.7% [n = 72]).

CONCLUSIONS

In contemporary US practice, off-label and untested use of drug-eluting stents is common. Compared with standard use, relative early safety is lower with off-label use, and the long-term effectiveness is lower with both off-label and untested use. However, the absolute event rates remain low.

A comparison of arterial closure devices to manual compression in liver transplantation candidates undergoing coronary angiography

Whether arterial closure devices can be used safely in a coagulopathic population undergoing cardiac catheterization and at high risk for groin complications, such as liver transplant candidates, is unknown. In this prospective, non-randomized consecutive series of 80 liver transplant candidates undergoing coronary angiography, manual compression and arterial closure devices were compared. Ilio-femoral angiography was performed to determine suitability for use of the closure device. Bleeding and vascular complications were recorded along with time to ambulation. Arterial closure devices were used in 31 patients (39%), whereas manual compression was used in 49 patients (50 procedures) (61%). There were no significant differences between the two groups with respect to age, sex, cardiac risk factors, peripheral vascular disease, baseline platelet count or baseline INR. There were 10 total vascular complications out of 50 procedures (20%) in the manual compression group compared to 2 vascular complications out of 31 procedures in the arterial closure device group (6%; p = 0.12). The time to ambulation was significantly less in the group receiving arterial closure devices versus manual compression (4.2 1.8 hours versus 6.6 3.7 hours, respectively; p = 0.0003). In coagulopathic patients at higher risk for groin complications, arterial closure devices can be safely used and decrease time to ambulation compared to manual compression.

Predictors of long-term outcomes following direct percutaneous coronary intervention for acute myocardial infarction

To determine predictors of a long-term major adverse cardiac event (MACE) in unselected patients undergoing direct percutaneous coronary intervention (PCI), 274 consecutive patients presenting within 12 hours of ST-segment elevation acute myocardial infarction (AMI) were evaluated. No patient with ST-segment elevation AMI received intravenous thrombolytic drugs. Chest pain to balloon time was 3.8 hours (range 2.5 to 6.9). percutaneous transluminal coronary angioplasty was successful in 95% of patients. Abciximab was administered to 69% of patients, stents were deployed in 53%, and 17% underwent only catheterization. In-hospital events were death (7%), abrupt closure (2%), emergent coronary artery bypass grafting (CABG) (5%), repeat PCI (3%), and recurrent myocardial infarction (1%). In patients undergoing direct PCI (n = 227), the in-hospital event rate was death 5.3%, abrupt closure 2.2%, emergency CABG 0.9%, repeat PCI 3.1%, and repeat myocardial infarction 1.3%. Median time to last follow-up or death was 20 months (range 11 to 34), and to any event, 0.3 months (range 0.03 to 24.0). Postdischarge MACE included death (5%), AMI (4%), repeat PCI (8%), CABG (9%), and stroke (0.7%). Among those undergoing direct PCI (n = 227), 10% died, 3.5% had a repeat AMI, 9% had a repeat PCI, 5% had CABG, and 1% had a stroke at long-term follow-up. At long-term follow-up, 75% were event free. Multivariate predictors were (hazard ratio [95% confidence interval (CI)]): abciximab use 0.6 (95% CI 0.43 to 0.95), Killip class 2.2 (95% CI 1.1 to 4.4), and number of narrowed coronary arteries 1.7 (95% CI 1.4 to 2.2). In this unselected consecutive series of patients presenting with ST-segment elevation AMI, direct PCI was associated with sustained long-term efficacy. Outcomes were predicted by cardiac impairment at presentation and number of narrowed coronary arteries. MACE is not related to device selection but is significantly improved with abciximab.

Incidence and angiographic predictors of side branch occlusion following high-pressure intracoronary stenting

We evaluated the incidence, angiographic predictors, and clinical outcome of side branch occlusion (SBO) following high-pressure intracoronary stenting in 175 patients. All stent implants during a 7-month period were reviewed for the incidence of major (>1 mm) SBO. Side branches were further characterized based on side branch and index lesion morphology. Clinical events (death, myocardial infarction, and target vessel revascularization rates) were determined at 9 months. A total of 175 patients (182 lesions) had 224 major side branches covered by intracoronary stents. Of these, 43 (19%) occluded. Most SBOs (29 of 43 [67%]) occurred after poststent dilation using high-pressure inflations (15.3 +/- 3.3 atmospheres). No clinical characteristics correlated with SBO. By multivariate analysis, those side branches with >50% ostial narrowing that arose from within or just beyond the diseased portion of the parent vessel (threatened side branch morphologies) were a powerful angiographic predictor of SBO (odds ratio 40, 95% confidence interval, 14 to 130, p <0.0001). At 9-month follow-up there was no difference in combined clinical events between those patients with and without SBO. These data demonstrate that side branches with ostial stenoses in continuity with diseased parent lesions were at risk of occlusion following stenting. SBO, however, was not associated with adverse clinical outcome. These findings lend support to plaque shift ("snow plow effect") as the mechanism behind SBO following stent placement.

Primary angioplasty reduces risk of myocardial rupture compared to thrombolysis for acute myocardial infarction

Although the mechanical complications of acute ventricular septal defect and acute mitral regurgitation are uncommon after acute myocardial infarction, these complications are associated with an extremely high morbidity and mortality. We hypothesized that the administration of thrombolytic drugs may result in hemorrhagic infarction as well as the potential for incomplete revascularization and thus may lead to an increased incidence of mechanical complications compared to primary angioplasty. Accordingly, we reviewed the data of the most contemporary thrombolytic and primary angioplasty trials and compared the incidence of mechanical complications among 36,303 patients treated with thrombolytics reported in the GUSTO trial to the incidence of mechanical complications among 1,295 patients treated with primary angioplasty obtained from the PAMI-1 and PAMI-2 trials. We found that angioplasty resulted in an overall 86% relative risk reduction in mechanical complications (2.20% vs. 0.31%, P < 0.001). In comparison to thrombolytic therapy, angioplasty resulted in an 82% decrease in acute mitral regurgitation (1.73% vs. 0.31%, P < 0.001) and a 100% decrease in acute ventricular septal defect (0.47% vs. 0.00%, P < 0.03). In conclusion, in patients with acute myocardial infarction, reperfusion with primary angioplasty is associated with less myocardial rupture and mechanical complications than thrombolytics. This finding may, in part, explain the improved prognosis observed in myocardial infarction patients treated with primary angioplasty.

Treatment of no-reflow in degenerated saphenous vein graft interventions: comparison of intracoronary verapamil and nitroglycerin

No-flow has been reported after 10-15% of percutaneous interventions on degenerated saphenous vein grafts. In this prospective study of 36 degenerated saphenous vein graft lesions (32 patients), no-flow (TIMI flow < 3 in the absence of a significant lesion or dissection) occurred in 15/36 (42%) lesions. A total of 32 episodes of no-flow occurred after angioscopy (n = 14), extraction atherectomy (n = 10), balloon angioplasty (n = 2) or stent implantation (n = 6). Intragraft nitroglycerin (100-300 micrograms) alone resulted in no improvement in TIMI flow in the setting of no-reflow (TIMI flow 1.2 +/- 0.6 to 1.4 +/- 0.8, P = NS). Intragraft verapamil (100-500 micrograms) resulted in improvement in flow in all 32 episodes (TIMI flow 1.4 +/- 0.8 before, to 2.8 +/- 0.5 after verapamil, P < 0.001). Although verapamil increased TIMI flow after all episodes of no-reflow, two (6.3%) had persistent no-reflow (TIMI 1) despite verapamil, associated with non-Q wave myocardial infarction. In conclusion, treatment of no-reflow with verapamil during degenerated vein graft interventions was associated with reestablishment of TIMI 3 flow in 88% of cases. In contrast, intragraft nitroglycerin alone was ineffective for reversing no-reflow.

Treatment of no-reflow in degenerated saphenous vein graft interventions: comparison of intracoronary verapamil and nitroglycerin

No-flow has been reported after 10-15% of percutaneous interventions on degenerated saphenous vein grafts. In this prospective study of 36 degenerated saphenous vein graft lesions (32 patients), no-flow (TIMI flow < 3 in the absence of a significant lesion or dissection) occurred in 15/36 (42%) lesions. A total of 32 episodes of no-flow occurred after angioscopy (n = 14), extraction atherectomy (n = 10), balloon angioplasty (n = 2) or stent implantation (n = 6). Intragraft nitroglycerin (100-300 micrograms) alone resulted in no improvement in TIMI flow in the setting of no-reflow (TIMI flow 1.2 +/- 0.6 to 1.4 +/- 0.8, P = NS). Intragraft verapamil (100-500 micrograms) resulted in improvement in flow in all 32 episodes (TIMI flow 1.4 +/- 0.8 before, to 2.8 +/- 0.5 after verapamil, P < 0.001). Although verapamil increased TIMI flow after all episodes of no-reflow, two (6.3%) had persistent no-reflow (TIMI 1) despite verapamil, associated with non-Q wave myocardial infarction. In conclusion, treatment of no-reflow with verapamil during degenerated vein graft interventions was associated with reestablishment of TIMI 3 flow in 88% of cases. In contrast, intragraft nitroglycerin alone was ineffective for reversing no-reflow.

Enhanced coronary vasoconstrictive response to serotonin subsides after removal of dietary cholesterol in atherosclerotic monkeys

Constriction in response to serotonin is enhanced in the coronary arteries of atherosclerotic monkeys. The main objective of the present study was to determine whether abnormal responses to serotonin in atherosclerosis are reversed following removal of dietary cholesterol. In addition, we examined the effect of an atherogenic diet and reduction in dietary cholesterol on vascular responses to activation of ATP-sensitive K+ channels with aprikalim. Diameters of small coronary arteries were measured on the epicardial surface of the left ventricle in vivo by using stroboscopic illumination synchronized to the heart cycle to visually freeze the motion of the heart. Diameters were measured with a microscope-video system during topical application of two vasoconstrictor agonists, serotonin and the thromboxane mimetic U46619, and the vasodilator agonists aprikalim and nitroprusside. Responses were compared in normal (n = 9), atherosclerotic (n = 14; high-cholesterol diet), and regression (n = 8; high-cholesterol diet followed by normal diet) monkeys. Constriction of coronary arteries in response to serotonin was enhanced in monkeys on an atherogenic diet and was normal in regression monkeys. Vasoconstriction in response to U46619 and vasodilation in response to nitroprusside and aprikalim were not altered by atherosclerosis. Thus, abnormal vascular responses to serotonin in small coronary arteries of atherosclerotic monkeys without morphological evidence of disease can be reversed to normal by reducing dietary cholesterol.

Functional improvement precedes structural regression of atherosclerosis

BACKGROUND

Vasoconstrictor responses to serotonin are augmented in monkeys with diet-induced atherosclerosis and improve after 18 months of normal diet. We tested the hypothesis that functional improvement may occur early during regression, before evidence of structural improvement.

METHODS AND RESULTS

Responses of the iliac artery to serotonin were measured by quantitative angiography and a Doppler flow probe in several groups of monkeys: (1) normal monkeys, (2) monkeys fed an atherogenic diet for 2 years (atherosclerotic), and (3) monkeys fed an atherogenic diet for 2 years (preregression) followed by a normal diet for 4, 8, or 12 months (regression). In normal monkeys, serotonin produced minimal constriction of the iliac artery, and blood flow to the legs increased. In atherosclerotic monkeys, there was pronounced constriction of the iliac artery, and blood flow to the legs decreased markedly. After 4 months of regression diet, four of eight monkeys demonstrated marked reduction in hyperresponsiveness to serotonin angiographically, and by 8 months, six of eight monkeys had significant improvement. After regression, serotonin produced minimal changes in flow. There was no reduction in intimal area (ie, atherosclerotic lesion) in iliac arteries from regression monkeys compared with atherosclerotic monkeys, but there was a marked reduction in cholesteryl ester in arteries from regression monkeys.

CONCLUSIONS

Abnormal vasoconstrictor responses to serotonin usually return to or toward normal within a few months during regression of atherosclerosis. Functional improvement occurs in conjunction with early resorption of lipid from the arterial wall and occurs before detectable changes in mass of the atherosclerotic lesion.

Transcatheter embolization of an internal mammary artery bypass graft sidebranch causing coronary steal syndrome

We describe a 66-yr-old man with angina after internal mammary artery-coronary bypass grafting due to coronary artery steal by a sidebranch of the mammary artery. Myocardial ischemia was successfully treated by transcatheter embolization of the sidebranch.