Percutaneous revascularization of occluded vein grafts : is it still a temptation to be resisted?

Unusual Retrograde Aortic Arch Dissection During Percutaneous Coronary Intervention

Coronary dissection is one of the most frequently occurring complications during coronary interventional procedures. However, extensive coronary dissection retrograde to the coronary sinus of Valsalva and to the arch of aorta is very rarely observed. The authors report a case of retrograde coronary dissection extending into the arch of aorta. Management and coronary angiography at 6-month follow-up are discussed.

Animal and in silico models for the study of sarcomeric cardiomyopathies

Over the past decade, our understanding of cardiomyopathies has improved dramatically, due to improvements in screening and detection of gene defects in the human genome as well as a variety of novel animal models (mouse, zebrafish, and drosophila) and in silico computational models. These novel experimental tools have created a platform that is highly complementary to the naturally occurring cardiomyopathies in cats and dogs that had been available for some time. A fully integrative approach, which incorporates all these modalities, is likely required for significant steps forward in understanding the molecular underpinnings and pathogenesis of cardiomyopathies. Finally, novel technologies, including CRISPR/Cas9, which have already been proved to work in zebrafish, are currently being employed to engineer sarcomeric cardiomyopathy in larger animals, including pigs and non-human primates. In the mouse, the increased speed with which these techniques can be employed to engineer precise 'knock-in' models that previously took years to make via multiple rounds of homologous recombination-based gene targeting promises multiple and precise models of human cardiac disease for future study. Such novel genetically engineered animal models recapitulating human sarcomeric protein defects will help bridging the gap to translate therapeutic targets from small animal and in silico models to the human patient with sarcomeric cardiomyopathy.

Comparison of percutaneous coronary intervention in native coronary arteries vs. bypass grafts in patients with prior coronary artery bypass graft surgery

OBJECTIVE

To compare the procedural and clinical outcomes of prior coronary artery bypass graft surgery (CABG) patients undergoing percutaneous coronary intervention (PCI) in native arteries vs. bypass grafts.

METHODS

The medical and catheterization records and the angiograms of 142 consecutive prior CABG patients who underwent 165 PCI of 247 lesions at our institution between January 1, 2003, and December 31, 2006, were retrospectively reviewed.

RESULTS

Mean age was 66+/-10 years and 99% were men: 79 and 63 patients underwent native coronary or bypass graft PCI, respectively. Compared to patients undergoing bypass graft PCI, those undergoing native coronary artery PCI were younger (mean age 64+/-10 vs. 68+/-10 years, P=.008), more likely to present with stable angina (29% vs. 8%, P=<.001), and presented earlier after CABG (after a mean of 9+/-6 vs. 12+/-5 years, P<.01). Compared to bypass graft PCI, native coronary PCI was more likely to be performed with drug-eluting stents (88% vs. 57%, P<.001) and was associated with lower risk of no-reflow (3% vs. 24%, P<.001). After a mean follow-up of 2.5+/-1.1 years, both groups of patients had similar but high incidence of myocardial infarction, repeat PCI, and death.

CONCLUSIONS

Prior CABG patients undergoing native coronary artery PCI have lower procedural risk, but similar postprocedural clinical outcomes compared to patients undergoing bypass graft PCI. If feasible, native coronary arteries may be the preferred PCI target in prior CABG patients.

The genetic basis for altered blood vessel function in disease: large artery stiffening

The progressive stiffening of the large arteries in humans that occurs during aging constitutes a potential risk factor for increased cardiovascular morbidity and mortality, and is accompanied by an elevation in systolic blood pressure and pulse pressure. While the underlying basis for these changes remains to be fully elucidated, factors that are able to influence the structure and composition of the extracellular matrix and the way it interacts with arterial smooth muscle cells could profoundly affect the properties of the large arteries. Thus, while age and sex represent important factors contributing to large artery stiffening, the variation in growth-stimulating factors and those that modulate extracellular production and homeostasis are also being increasingly recognized to play a key role in the process. Therefore, elucidating the contribution that genetic variation makes to large artery stiffening could ultimately provide the basis for clinical strategies designed to regulate the process for therapeutic benefit.

Utilization of a Double-Wire Technique to Treat Long Extended Spiral Dissection of the Right Coronary Artery: Evaluation of Incidence and Mechanisms

While coronary artery dissection caused by a guiding catheter, which is one of the most commonly occurring complications during diagnostic cardiac catheterization or coronary intervention, has various forms, extensive antegrade and retrograde dissections of the right coronary artery (RCA) are rarely observed during these procedures. Within the last three years, we retrospectively reviewed our experience with 12,600 consecutive patients who underwent either diagnostic cardiac catheterization or coronary angioplasty, and found that 17 (0.14%) of the patients displayed extensive antegrade and retrograde RCA dissection. The antegrade dissection always propagated to the distal RCA either on bifurcation of the posterior descending artery and posterolateral artery (PLA) or to the proximal PLA. The retrograde dissection was always observed close to the ostium of the RCA or extending to the ostium of the RCA. TIMI-0 flow in the RCA was immediately observed in all the patients. Chest pain associated with an electrocardiogram showing ST-segment elevation was soon observed in most of the patients. The true lumen could be entered successfully using a single wire in 8 of 17 patients. However, a double-wire technique was required for 7 patients. This technique involved first advancing a wire along to the false lumen and then pulling back the guiding catheter away from the ostium of the RCA for a few millimeters followed by anchoring with the wire. Another wire was then gently inserted into the true lumen from the dissection entrance point, which was located near or at the ostium of RCA, and carefully advanced to the distal RCA. Coronary stenting was successfully deployed in 15 patients. However, the procedure failed in 2 patients. Furthermore, this complication caused 7 patients to have acute myocardial infarctions, 2 patients to develop atrial fibrillation, and I to die from ischemic enterocolitis due to cardiac embolism after 7 months of follow-up. In conclusion, with an increase in experience, we now better understand this complication. However, this complication, which is a formidable challenge for coronary intervention, may be a life-threatening complication, and patients with this complication may face the potential risk of a nonfatal myocardial infarction, or even a long-term fatal outcome in the long-term. Accordingly, it is important to learn how to promptly manage this complication.

A randomized trial of polytetrafluoroethylene-membrane-covered stents compared with conventional stents in aortocoronary saphenous vein grafts

We compared a conventional stent (Jostent Flex, Jomed GmbH, Rangendingen, Germany) with a polytetrafluoroethylene (PTFE)-membrane-covered stent (Jostent Stentgraft) in patients undergoing intervention of a stenosis in an obstructed vein graft. The use of stents improved results of percutaneous revascularization of obstructed vein grafts, but did not demonstrate the reduced elevated restenosis rate. In addition, long-term clinical event rate is still high compared with intervention in native vessels. Observational studies suggested that stents covered with a PTFE membrane might be associated with a low complication and restenosis rate in venous bypass grafts. This prospective multicenter study included a total of 211 patients who were randomly assigned to receive either a Flex stent or Stentgraft. The primary end point was binary restenosis rate at six months by core lab quantitative coronary angiography. Acute success and procedural events were comparable between the two groups. Restenosis rate was not significantly different between the Flex (20%) and the Stentgraft (29%) groups (p = 0.15), although there was a nonsignificant trend toward a higher late occlusion rate in the Stentgraft group (7% vs. 16%, p = 0.069) at follow-up. Likewise, after a mean observation period of 14 months, cumulative event rates (death, myocardial infarction, or target lesion revascularization) were comparable in the two groups (31% vs. 31%, p = 0.93). This controlled trial does not indicate a superiority of the PTFE-membrane-covered Stentgraft compared with a conventional stent with respect to acute results, restenosis, or clinical event rates.

Unusual complication of retrograde dissection to the coronary sinus of valsalva during percutaneous revascularization: a single-center experience and literature review

BACKGROUND

While coronary dissection, which is one of the most frequently occurring complications during interventional procedures, has various forms, extensive coronary dissection retrograde to the coronary sinus of Valsalva (CSV) is very rarely observed.

METHODS AND RESULTS

Within the last 5 years, we retrospectively reviewed our experience with 4,700 consecutive patients who underwent angioplasty procedures, 7 of whom (0.15%) developed extensive coronary dissection retrograde to the CSV. Six of the seven patients developed retrograde dissection of the right CSV during angioplasty to the right coronary artery. One of the seven patents developed retrograde dissection of the left CSV during angioplasty to the left anterior descending artery. Retrograde dissection, which extended to the ascending aorta in two patients, was observed by transthoracic echocardiography and surgical findings, respectively. Five patients were successfully treated by coronary stenting. However, this complication caused four patients to have acute myocardial infarctions, resulting in emergency surgery for one patient and in-hospital death for another.

CONCLUSIONS

Our experience increased our understanding of this very rare complication. However, this complication may be life threatening, and patients in this clinical setting may have a potential risk for acute myocardial infarction, emergency surgery, or even sudden cardiac death. Therefore, it is important to learn how to promptly diagnose and manage this complication.

Long-term clinical outcome after endoluminal reconstruction of diffusely degenerated saphenous vein grafts with less-shortening wallstents

OBJECTIVES

This study was designed to evaluate the immediate and long-term clinical results of patients undergoing endoluminal reconstruction in diffusely degenerated saphenous vein grafts (SVGs) with elective implantation of one or more less-shortening Wallstents.

BACKGROUND

The optimal treatment strategy for patients with diffusely degenerated SVGs is controversial. Endoluminal reconstruction by stent implantation is one proposed strategy; however, there are few data regarding long-term clinical outcome.

METHODS

Between May 1995 and September 1998, 6,534 consecutive patients underwent angioplasty in our institution, including 440 who were treated for SVG lesions. Of these, 126 (115 men, 11 women, median age 69.5 years, range: 33-86 years) with old SVGs (mean age: 13+/-5 years) diffusely degenerated stenosed or occluded (mean lesion length: 27+/-12 mm) were treated electively with implantation of one or multiple (total 197) less-shortening Wallstents.

RESULTS

Before discharge, 13 patients (10.3%) sustained at least one major cardiovascular event, including 4 deaths (3.2%), 11 myocardial infarctions (MI) (8.7%), and 3 repeat revascularizations (target vessel = 1, nontarget vessel = 2, 2.4%). Surviving patients were followed for 22+/-11 months: 13 patients (11.1%) died, 11 (9.4%) sustained an MI, 37 underwent angioplasty (31.6%), and 4 (3.4%) underwent bypass surgery. The estimated three-year event-free survival rates (freedom from death, and freedom from death/MI/target vessel revascularization) were (mean +/- SE) 81.1+/-7.8% and 43.2+/-18.5%, respectively.

CONCLUSIONS

The long-term clinical outcome of patients undergoing endoluminal reconstruction in diffusely degenerated SVG is relatively poor, mainly because of a high incidence of death or MI and the frequent need for repeat angioplasty. It is unlikely that percutaneous intervention alone will provide a satisfactory or definitive solution for these patients.

Coronary microembolization--its role in acute coronary syndromes and interventions

The diagnosis coronary artery disease is classically based on patient's symptoms and morphology, as analyzed by angiography. The importance of risk factors for the development of coronary atherosclerosis and disturbance of coronary vasomotion is clearly established. However, microembolization of the coronary circulation has also to be taken into account. Microembolization may occur as a single or as multiple, repetitive events, and it may induce inflammatory responses. Spontaneous microembolization may occur, when the fibrous cap of an atheroma or fibroatheroma (Stary i.v. and Va) ruptures and the lipid pool with or without additional thrombus formation is washed out of the atheroma into the microcirculation. Such events with progressive thrombus formation are known as cyclic flow variations. Plaque rupture occurs more frequently than previously assumed, i.e. in 9% of patients without known heart disease suffering a traffic accident and in 22% of patients with hypertension and diabetes. Also, in patients dying from sudden death microembolization is frequently found. Patients with stable and unstable angina show not only signs of coronary plaque rupture and thrombus formation, but also microemboli and microinfarcts, the only difference between those with stable and unstable angina being the number of events. Appreciation of microembolization may help to better understand the pathogenesis of ischemic cardiomyopathy, diabetic cardiomyopathy and acute coronary syndromes, in particular in patients with normal coronary angiograms, but plaque rupture detected by intravascular ultrasound. Also, the benefit from glycoprotein IIb/IIIa receptor antagonist is better understood, when not only the prevention of thrombus formation in the epicardial atherosclerotic plaque, but also that of microemboli is taken into account. Microembolization also occurs during PTCA, inducing elevations of troponin T and I and elevations of the ST segment in the EKG. Elevated baseline coronary blood flow velocity, as a potential consequence of reactive hyperemia in myocardium surrounding areas of microembolization, is more frequent in patients with high frequency rotablation than in patients with stenting and in patients with PTCA. The hypothesis of iafrogenic microembolization during coronary interventions is now supported by the use of aspiration and filtration devices, where particles with a size of up to 700 microns have been retrieved. In the experiment, microembolization is characterized by perfusion-contraction mismatch, as the proportionate reduction of flow and function seen with an epicardial stenosis is lost and replaced by contractile dysfunction in the absence of reduced flow. The analysis of the coronary microcirculation, in addition to that of the morphology and function of epicardial coronary arteries, and in particular appreciation of the concept of microembolization will further improve the understanding of the pathophysiology and clinical symptoms of coronary artery disease.