Drug-eluting stents, since their approval in the United States, have become the treatment of choice for de novo coronary artery narrowing due to their ability to reduce restenosis and the need for repeat revascularization. We present two patients who underwent percutaneous coronary intervention for the treatment of multivessel coronary artery disease; both patients were treated with sirolimus-eluting stents (SES) and bare metal stents (BMS).
Here, we present a case of a 63-year-old male who presented with in-stent restenosis of two coronary arteries simultaneously (mid circumflex and proximal ramus). After the brachytherapy of the circumflex artery for in-stent restenosis, the patient refused the staged procedure for the ramus in-stent restenosis. After approximately 2 years, the patient underwent coronary angiography for recurrent chest pain. Surprisingly, the proximal ramus stent showed marked regression of in-stent restenosis. We hypothesized that the gamma brachytherapy of the circumflex artery could have induced the regression of in-stent restenosis of the adjacent ramus artery due to the deep tissue penetration of gamma radiation. Based on our observation, we believe that in the treatment of in-stent restenosis of a coronary artery, the initial balloon angioplasty may not be as important as the radiation itself. This observation warrants further study to evaluate the effect of external or internal radiation on in-stent restenosis without balloon angioplasty. If our hypothesis is confirmed, the treatment of in-stent restenosis with external radiation could substantially simplify the treatment of this disease. This case report follows a brief review of the literature.
Vascular brachytherapy (VBT) is effective for the treatment of in-stent restenosis (ISR), however, the effect of VBT clinical and angiographic outcomes of patients with ISR who have undergone orthotopic heart transplantation (OHT) requires further study.
All OHT patients with ISR treated with VBT using the Novoste Beta-Cath System at Rush University Medical Center were identified, and the clinical and angiographic outcomes were evaluated.
Four OHT patients with ISR who underwent VBT were identified. The mean age was 48.5 years, and the mean duration posttransplantation was 7.5 years. The mean reference coronary vessel diameter was 3.06 mm. The primary interventional device utilized prior to VBT was cutting balloon angioplasty (CBA) in 75% and percutaneous balloon angioplasty in 25%. The mean duration of follow-up after VBT was 11 months. There were no deaths attributable due to cardiac disease, no myocardial infarction, and no target vessel revascularization on follow-up. Overall survival during this period was 75%, with one mortality due to stroke 8 months after VBT.
VBT for the treatment of ISR in patients who have undergone OHT appears safe and feasible and is associated with acceptable clinical and angiographic outcomes.
Mechanical injury from balloon angioplasty and stenting is known to cause prolonged endothelial dysfunction, even distal to the injured segment. Intravascular irradiation therapy is associated with delayed healing response and may therefore also impede endothelial functional recovery. This study was conducted to assess endothelial function late after the irradiation of atherosclerotic coronary arteries.
In 15 patients (8 with additional radiation and 7 with stenting only), directly after the intervention and at 6-month follow-up, endothelial function of the distal segment was studied by assessment of coronary diameter after intracoronary acetylcholine (Ach). Coronary flow reserve (CFR) and intravascular ultrasound (IVUS) investigation were performed for unequivocal interpretation of angiographic data.
No significant different response to Ach could be detected at baseline nor at follow-up (−17±14% vs. −17±15% for radiation vs. nonradiation at baseline, P=1.0; −8±11% vs. −9±13% at follow-up, P=.8). IVUS data revealed more constrictive remodeling in the nonradiation patients, but a minimal increase in mean plaque area in the radiation patients compared with a significant decrease in nonradiation patients (+4% vs. −25%, P=.02).
Irradiation of atherosclerotic coronary arteries does not affect endothelium-dependent vasodilatation acutely or at 6 months. Irradiated segments demonstrated less negative remodeling but higher plaque burden than the controls did.
Nitric oxide (NO) has an important effect on blood pressure, arterial wall, and the basal release of endothelial NO in hypertension (HPN) may be reduced. Until now, there is no solid data revealing the potential role of the polymorphism of the nitric oxide synthase gene (NOS) in patients with HPN and microvascular angina.
The aim of the present study is to investigate the gene of endothelial nitric oxide synthase (eNOS), as the polymorphism of this gene may be a putative candidate for HPN and initiate the process of atherosclerosis.
Sixty participants were recruited for this study; 50 were hypertensive patients complaining of chest pain [30 of them have electrocardiogram (EKG) changes of ischemia], 20 had isolated HPN, and 10 healthy volunteers served as control. All patients underwent stress myocardial perfusion imaging (MPI) and coronary angiography. Genotyping of eNOS for all patients and controls was performed. The linkages between HPN, microvascular angina and eNOS gene polymorphism were investigated.
MPI and coronary angiography revealed that 15 patients had chest pain with true ischemia and reversible myocardial perfusion defects (multiple and mild) but normal epicardial coronary arteries (microvascular angina), while 15 patients had significant coronary artery disease (CAD), and 20 hypertensive patients showed normal perfusion scan and coronary angiography. The prevalence of the NOS G298 allele was higher in the hypertensive group with microvascular angina (documented by MPI) than it was among the control participants (P<.005). The eNOS allele was significantly higher in the hypertensive group than in the control participants, but there was no significant difference in homozygote mutants among hypertensive participants, x-syndrome and patients with CAD.
eNOS gene polymorphism is proved to be an important etiology in microvascular angina (x-syndrome) among hypertensive patients. In addition, the eNOS mutant gene showed a significant increase in isolated HPN and in patients with CAD.
The objective of this study was to determine the clinical and angiographic profile of patients with extremely high coronary artery calcium scores (CACS; ≥1000) by electron beam computed tomography (EBCT).
All patients at Rush University Medical Center who had a calcium score ≥1000 and a coronary angiogram performed from 1997 to 2002 were identified using a prospectively collected database. The baseline demographics, symptom status, and degree of coronary stenosis by angiography and subsequent rate of coronary intervention were compared with that of patients with calcium scores <1000.
The clinical and angiographic profile of patients with severe coronary calcification, detected by EBCT, revealed that patients with scores ≥1000 had a significantly higher prevalence of coronary stenosis ≥50% compared with patients with scores <1000 (97% vs. 57%, P<.001). The group with CACS ≥1000 was more likely to be male (90% vs. 75%, P=.027) and was older (64±8 vs. 59±10, P=.001) compared with the group with less severe calcification. Although there was a significantly higher rate of luminal stenosis detected by coronary angiography in the cohort with CACS ≥1000, there was no difference in subsequent percutaneous coronary intervention (PCI) and utilization of intracoronary stents between the two groups.
A markedly elevated coronary calcium score (≥1000) is correlated with increasing age and is associated with an increased likelihood of coronary stenosis ≥50%. However, the decision to perform coronary angiography in patients with severe coronary calcification should not be based solely on these findings, but should remain primarily dependent on the degree of ischemia detected by clinical and functional assessment.
The advent of drug-eluting stents has provided the interventional cardiologist an effective new tool in treating coronary restenosis. There remains, however, a small group of patients that still require intervention following drug-eluting stent therapy. Currently, intravascular brachytherapy (IVBT) is approved for use in the treatment of in-stent restenosis (ISR). This study investigated the effect of gamma and beta radiation doses typically used in IVBT on the performance of the TAXUS Express2 paclitaxel-eluting stent.
It was determined that there were no statistically significant changes to in vitro paclitaxel release from stent exposed to radiation compared to controls subjected to the same conditions except for the radiation exposure. The molecular weight of the Translute polymer carrier matrix and the level of paclitaxel degradants were not changed following exposure to radiation doses up to twice what is typically used in IVBT. Beta and gamma radiation doses typically used in IVBT had no significant effect on the Translute polymer carrier, paclitaxel degradation, or paclitaxel release in this in vitro model.
The data are encouraging and support further evaluation of the use of IVBT in the treatment of ISR in the presence of drug-eluting stents.
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