Intervention in coronary artery disease

Balloon Angioplasty - The Legacy of Andreas Grüntzig, M.D. (1939-1985)

In 1974, at the Medical Policlinic of the University of Zürich, German-born physician-scientist Andreas Grüntzig (1939-1985) for the first time applied a balloon-tipped catheter to re-open a severely stenosed femoral artery, a procedure, which he initially called "percutaneous transluminal dilatation". Balloon angioplasty as a therapy of atherosclerotic vascular disease, for which Grüntzig and Charles T. Dotter (1920-1985) received a nomination for the Nobel Prize in Physiology or Medicine in 1978, became one of the most successful examples of translational medicine in the twentieth century. Known today as percutaneous transluminal angioplasty (PTA) in peripheral arteries or percutaneous transluminal coronary angioplasty (PTCA) or percutaneous coronary intervention (PCI) in coronary arteries, balloon angioplasty has become the method of choice to treat patients with acute myocardial infarction or occluded leg arteries. On the occasion of the 40(th) anniversary of balloon angioplasty, we summarize Grüntzig's life and career in Germany, Switzerland, and the United States and also review the developments in vascular medicine from the 1890s to the 1980s, including Dotter's first accidental angioplasty in 1963. The work of pioneers of catheterization, including Pedro L. Fariñas in Cuba, André F. Cournand in France, Werner Forssmann, Werner Porstmann and Eberhard Zeitler in Germany, António Egas Moniz and Reynaldo dos Santos in Portugal, Sven-Ivar Seldinger in Sweden, and Barney Brooks, Thomas J. Fogarty, Melvin P. Judkins, Richard K. Myler, Dickinson W. Richards, and F. Mason Sones in the United States, is discussed. We also present quotes by Grüntzig and excerpts from his unfinished autobiography, statements of Grüntzig's former colleagues and contemporary witnesses, and have included hitherto unpublished historic photographs and links to archive recordings and historic materials. This year, on June 25, 2014, Andreas Grüntzig would have celebrated his 75(th) birthday. This article is dedicated to his memory.

Effects of the simultaneous use of drug-eluting stents and statins in an atherosclerotic animal model

INTRODUCTION

The use of statins and medicated stents (MS) is the best available therapy for the treatment of severe coronary disease in selected cases. However, the vascular effects of the simultaneous use of both therapies are unknown.

MATERIALS AND METHODS

An experimental study was carried out on 60 NZ rabbits with advanced atherosclerosis, distributed in four groups of 15 animals each. Group 1: Control. Group 2: paclitaxel-eluting stent (PES) in the thoracic aorta. Group 3: Atorvastatin 2.5mg/day po+PES implant, and Group 4: Atorvastatin 2.5mg/day po. They were followed up at 30, 60 and 90 days. Histo-morphometric analyses were carried out.

RESULTS

A total of 60 PES were successfully implanted. One animal from Group 3 died due to respiratory infection. PES increased the lumen diameter and area, as well as the vessel area; atorvastatin induced a potent plaque regression. In the PES group, the lumen diameter was 4.25±0.0mm, lumen area was 14.2±0.4mm(2), vessel area was 16.7±0.0mm(2), and plaque/media area ratio was 0.1±0.0. In the PES+atorvastatin group the measurements were 4.9±0.1mm (p<0.001), 18.6±0.8mm(2) (p=0.005), 21.6±0.9mm(2) (p=0.007) and 0.8±0.08 (p=0.032), respectively.

CONCLUSIONS

Our results confirm the potent synergistic mechanical effect of the PES and plaque regression of the statins in an animal model with advanced atherosclerosis.

In vivoassessment of coronary artery angioplasty and stent deployment from balloon pressure–volume data

This study assessed the clinical and practical value of angioplasty balloon pressure-volume data, obtained by a computer-controlled balloon inflation device, during standard percutaneous coronary intervention (PCI) procedures. Stent deployment was studied for 57 lesions in 34 patients. Angiographic predilation data were available in 9 patients. Vessel lumen improvement with pre-dilation was determined using the area difference under the pressure-volume curves of two consecutive inflations and compared to the angiographically determined lumen improvement. Stent opening pressure, the inflation volume needed to unfold the stent and the shape of the pressure-volume curve were assessed for differences between stent sizes (diameter, length) and manufacturer types. A Pearson correlation of 0.8 between the pressure-volume area difference and the angiographic lumen improvement was significant (p = 0.01), confirming that pressure-volume curves are useful in assessing lumen improvement after pre-dilation. There was a significant difference in stent opening pressure between stent types but not between different stent sizes (length, diameter). The inflation volume measured during the unfolding process of the stent correlated with the calculated stent lumen when deployed (Pearson correlation: 0.65, p = 0.001). The shape of the pressure-volume curve during stent deployment illustrated differences between different stent sizes (length, diameter) during inflation. Pressure-volume curves obtained from an automatic balloon inflation device have shown their usefulness in providing additional feedback about lumen improvement and the mechanical characteristics and quality of stent deployment.

Clinical impact of drug-eluting stents in changing referral practices for coronary surgical revascularization in a tertiary care center

BACKGROUND

The long-term benefits of angioplasty are limited by the occurrence of restenosis. Drug-eluting stents with a projected restenosis rate of close to 0% are soon to become available. The short- and long-term consequences of this advance to the cardiac surgical volume remain unclear.

METHODS

A total of 196 consecutive coronary angiograms and medical records of patients referred for coronary bypass surgery were reviewed. Considering the hypothetical premise of having drug-eluting stents with a near zero restenosis rate, we reviewed each case to determine if surgical revascularization was still the preferred option for revascularization.

RESULTS

The mean age was 60 (+/-10.6) years. Seventy-two percent of patients were male. Considering the availability of drug-eluting stents 154 (79%) would still have been sent to surgery, representing a 21% decrease in the number of surgical revascularizations. Angiographic characteristics predicting coronary bypass revascularization were the presence of chronic total occlusion (odds ratio [OR]: 9.1; confidence interval [CI]: 2.1 to 39), left main coronary artery stenosis (OR: 9.6; CI: 1.27 to 73), and need for valvular surgery (OR: 7.38; CI: 1.3 to 157). The most common predictors of a change in clinical management from surgical to percutaneous revascularization if drug-eluting stents were available were diffuse coronary narrowing (OR: 15.78), restenotic lesions (OR: 27.86), and small coronary arteries (OR: 26).

CONCLUSIONS

Drug-eluting stents may have a significant impact on cardiac surgery volume (approximately a 21% decrease in our center). It may also direct patients with small vessels, diffuse narrowing, or restenotic lesions and diabetic patients to percutaneous therapy.

Primary stenting versus MIDCAB: preliminary report-comparision of two methods of revascularization in single left anterior descending coronary artery stenosis

BACKGROUND

Percutaneous revascularization is a well-accepted method of treatment for a single left anterior descending coronary artery (LAD) stenosis. With the introduction of primary stenting, it has become the treatment of choice for a LAD lesion. In the last few years however, the introduction of minimally invasive cardiac surgery, video-assisted left internal thoracic artery (LITA) harvesting, and robotic surgery have raised the question as to whether minimally invasive surgical revascularization would be competitive with percutaneous coronary interventions in cases of single-vessel stenoses.

METHODS

A group of 100 patients with Canadian Cardiovascular Society class II to IV, and angiographically confirmed single critical stenosis of the LAD (type A or B), were treated with direct primary stenting (group 1, n = 50), or with endoscopic atraumatic coronary artery bypass grafting (group 2, n =50).

RESULTS

All patients in a group 1, obtained a very good angiographic and clinical effect. No acute postoperative complications were noted at 1 month of follow-up. However, at 1 month of follow-up, 3 patients (6%) developed restenosis of the LAD, and at 6 months follow-up, 6 patients (12%), developed restenosis of the LAD. In these cases, repeated percutaneous coronary interventions of the target vessel were successfully performed. In group 2, very good operative results were observed. In 1 and 6 months of follow-up, all patients remained asymptomatic. Critical stenosis of the left internal thoracic artery-LAD anastomosis was angiographically documented in 1 case (2%). This patient was successfully treated with balloon angioplasty.

CONCLUSIONS

The study results document the superiority of endoscopic atraumatic coronary artery bypass grafting over direct primary stenting in LAD revascularization, along with the slightly higher costs of the surgical procedure.

Adequate patient selection for coronary revascularization: an overview of current methods used in daily clinical practice

Widely used non-invasive stress modalities, like exercise ECG, MPS and stress-echocardiography, are the tests of first choice for the diagnosis of CAD. It has been shown in numerous studies that non-invasive assessment of perfusion abnormalities is an adequate strategy for risk stratification. Moreover, non-invasive stress testing should be performed before a diagnostic cardiac catheterization to document the presence of myocardial ischemia, as a prerequisite for coronary revascularization. Coronary angiography is the gold standard for identifying CAD; however this technique is limited in assessing functional severity of coronary narrowings ('illusion of luminology'; see also Figure 5). The recently introduced i.c. hemodynamic parameters (CFVR and FFR) can identify functional severity of specific lesions and have shown a good agreement with the results of non-invasive stress test in validation studies. Furthermore, there is accumulating evidence that it is safe to defer a PTCA procedure, based on normal FFR and CFVR values. As these indices are derived during an invasive cardiac catheterization procedure, its use is recommended during a so called 'ad hoc' PTCA setting. Furthermore, they are particularly useful for clinical decision making in patients with documented multivessel CAD, as both indices allow selective evaluation of coronary narrowings in different arteries. Revascularization procedures are costly and always have a potential risk. It is important to be aware that, using above mentioned methods, unnecessary interventions (lacking potential benefit) may be avoided.

Trials comparing coronary artery bypass grafting with percutaneous transluminal coronary angioplasty and primary stent implantation in patients with multivessel coronary artery disease

With marked improvements in stent technology as adjunct to balloon angioplasty for multivessel coronary disease, several newer trials are currently in progress reviewing the optimal revascularization strategy. This review provides background from older studies and addresses the current progress and design of these newer trials.