Effect of Rotablator atherectomy and adjunctive balloon angioplasty on coronary blood flow

Long -term results of transradial rotational atherectomy for heavily calcified coronary artery lesions

Objective:

Percutaneous coronary intervention (PCI) for the heavily calcified coronary lesions remains a challenge, and the periprocedural complication rates of the transfemoral approach are high. This study was conducted to investigate the feasibility and long-term results of the transradial approach for rotational atherectomy (RA) prior to stent implantation via the transradial approach in patients with heavily calcified coronary artery lesions.

Methods:

RA followed by stent implantation via the transradial approach was performed in 47 patients with severely calcified coronary artery lesions in this retrospectively case-control study. The success rate of the procedure and the 3-year follow-up (36±7.5 months) results were analyzed.

Results:

RA with subsequent stent implantation or balloon angioplasty procedures were successfully performed in all cases. 6F guiding catheters were used in 45 cases, and 7F catheters were used in 2 patients. Rotablation was performed with a 1.25-mm burr in 29 cases, a 1.25-mm burr followed by a 1.5-mm burr in 17 patients, and a 1.75-mm burr in 1 patient. Percutaneous transluminal coronary angioplasty after RA was performed, followed by stent implantation in all 47 patients. Restenosis was found in 7 cases (7/38) at 13 months (13±3.6) and in 13 cases (13/28) at 36 months (36±7.5) after the procedure; 3 patients died during the 3-year follow-up. The post-procedure cumulative 3-year event-free survival rate was 78%.

Conclusion:

RA prior to stent implantation via the transradial approach is feasible and safe, the success rate is high, and long-term outcome is satisfactory in patients with heavily calcified lesions of the coronary artery.

Cardioprotective effect of high-dose intragraft adenosine infusion on microvascular function and prevention of no-reflow during saphenous vein grafts intervention

BACKGROUND

Despite the use of embolic protection devices, no-reflow can still occur during saphenous vein grafts (SVGs) intervention. High-dose intracoronary adenosine infusion preconditions the myocardium, improves coronary flow, and prevents no-reflow. The role of high-dose intragraft adenosine infusion on protection of microvascular function and prevention of no-reflow has not been investigated

OBJECTIVES

We investigated the cardioprotective effect of high-dose intragraft adenosine infusion, compared with placebo, on microvascular function and prevention of no-reflow during SVGs intervention.

METHODS

We randomized 22 patients with SVGs stenoses to receive either a 10-min intragraft adenosine infusion (200 μg/min; total dose = 2,000 μg) or normal saline prior to stenting. Average peak velocity (APV), coronary flow velocity reserve (CVR), thrombolysis in myocardial infarction (TIMI) frame count (TFC), TIMI myocardial perfusion grade (TMPG), and the rate of no-reflow were compared between the two groups before adenosine or saline infusions and after stenting

RESULTS

After stenting, hyperemic APV, CVR, and TMPG were significantly higher in the adenosine-treated group than in the control group (60 ± 18 vs. 35 ± 10 cm/sec; 2.6 ± 0.54 vs. 1.8 ± 0.47; and 2.8 ± 0.90 vs. 2.1 ± 0.80, respectively; P < 0.05. TFC was significantly lower in the adenosine-treated group than in the control group (14 ± 3.0 vs. 26 ± 13; P < 0.05). In the control group, four patients (36%) developed no-reflow compared to none in the adenosine-treated patient; P < 0.05 CONCLUSIONS: This study provides the first evidence that high-dose intragraft adenosine infusion compared with placebo protects microvascular function and prevents no-reflow during SVGs intervention.

Hemodynamic changes in a model of chronic heart failure induced by multiple sequential coronary microembolization in sheep

Although a large variety of animal models for acute ischemia and acute heart failure exist, valuable models for studies on the effect of ventricular assist devices in chronic heart failure are scarce. We established a stable and reproducible animal model of chronic heart failure in sheep and aimed to investigate the hemodynamic changes of this animal model of chronic heart failure in sheep. In five sheep (n = 5, 77 +/- 2 kg), chronic heart failure was induced under fluoroscopic guidance by multiple sequential microembolization through bolus injection of polysterol microspheres (90 microm, n = 25.000) into the left main coronary artery. Coronary microembolization (CME) was repeated up to three times in 2 to 3-week intervals until animals started to develop stable signs of heart failure. During each operation, hemodynamic monitoring was performed through implantation of central venous catheter (central venous pressure [CVP]), arterial pressure line (mean arterial pressure [MAP]), implantation of a right heart catheter {Swan-Ganz catheter (mean pulmonary arterial pressure [PAP mean])}, pulmonary capillary wedge pressure (PCWP), and cardiac output [CO]) as well as pre- and postoperative clinical investigations. All animals were followed for 3 months after first microembolization and then sacrificed for histological examination. All animals developed clinical signs of heart failure as indicated by increased heart rate (HR) at rest (68 +/- 4 bpm [base] to 93 +/- 5 bpm [3 mo][P < 0.05]), increased respiratory rate (RR) at rest (28 +/- 5 [base] to 38 +/- 7 [3 mo][P < 0.05]), and increased body weight 77 +/- 2 kg to 81 +/- 2 kg (P < 0.05) due to pleural effusion, peripheral edema, and ascites. Hemodynamic signs of heart failure were revealed as indicated by increase of HR, RR, CVP, PAP, and PCWP as well as a decrease of CO, stroke volume, and MAP 3 months after the first CME. Multiple sequential intracoronary microembolization can effectively induce myocardial dysfunction with clinical and hemodynamic signs of chronic ischemic cardiomyopathy. The present model may be suitable in experimental work on heart failure and left ventricular assist devices, for example, for studying the impact of mechanical unloading, mechanisms of recovery, and reverse remodeling.

An evidence-based approach to the use of rotational and directional coronary atherectomy in the era of drug-eluting stents: when does it make sense?

Advances in percutaneous interventions have profoundly changed the way we manage patients with coronary and peripheral arterial disease. Though the use of stents, particularly drug-eluting stents, is the preferred method for revascularization because of ease of use and lower restenosis rates, there are many short comings. Ostial and bifurcation lesions as well as heavily calcified and tortuous arteries remain problematic. Mechanical debulking with rotational and direct coronary atherectomy may be beneficial in these situations. In this review, we present the general concepts of mechanical debulking and attempt to summarize the available data on its use in the setting of drug-eluting stents. In addition, we will discuss its special role in the management of peripheral arterial disease.

123I-MIBG imaging can be used to evaluate microvascular disturbance caused by embolization by microdebris after rotational atherectomy

BACKGROUND

During rotational atherectomy (RA), the coronary atherosclerotic plaque is largely pulverized into microdebris, which may cause serious hemodynamic instability owing to significant segmental left ventricular asynergy embolization of the distal microvasculature by atheromatous debris and associated vasospasm.

OBJECTIVE

To evaluate the usefulness of 123I-metaiodobenzylguanidine (123I-MIBG) in the examination of microvascular embolization after RA.

METHODS AND RESULTS

Nineteen patients with stable effort angina pectoris who had undergone RA were evaluated in this study. Left ventricular ejection fraction (LVEF) was determined by left ventriculography immediately before and after RA. The serum concentration of creatine phosphokinase (CPK), creatine phosphokinase-myocardial band (CPK-MB) isozyme, and cardiac troponin-T was determined after RA. 99mTc-methoxyiso-butylisonitrile (99mTc-MIBI) and 123I-MIBG scintigraphic examinations were also performed 1 day after RA. The regional defect score (RDS) was determined from 99mTc-MIBI scintigraphic findings, while early and delayed RDS, heart-to-mediastinum count ratios (H/M ratios), and washout rate (WR) were determined from 123I-MIBG scintigraphy. After RA, the left ventriculographic LVEF mildly decreased by <10% in ten patients (group A), but it decreased by >10% in the remaining nine patients (group B). There were no differences in baseline clinical characteristics between the two groups. The CPK, CPK-MB isozyme, troponin-T, RDS by 99mTc-MIBI, H/M ratios, and WR after RA were similar in the two groups. However, the RDSs determined from early and delayed 123I-MIBG in group A were significantly lower than those in group B (4.5 +/- 3.8 vs. 13.4 +/- 10.8, P < 0.05; 9.0 +/- 6.3 vs. 17.7 +/- 10.0, P < 0.05, respectively). Moreover, there were significant correlations between delta LVEF and troponin-T (r = 0.54, P < 0.05) and RDSs of early and delayed 123I-MIBG (r = 0.46, P < 0.05; r = 0.64, P < 0.05, respectively).

CONCLUSIONS

These findings suggest that 123I-MIBG imaging can be used to evaluate microvascular disturbance caused by embolization by microdebris after RA.

Coronary microembolization

Atherosclerotic plaque rupture is the key event in the pathogenesis of acute coronary syndromes and it also occurs during coronary interventions. Atherosclerotic plaque rupture does not always result in complete thrombotic occlusion of the epicardial coronary artery with subsequent impending myocardial infarction, but may in milder forms result in the embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. This review summarizes the present experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and highlights the main consequences of coronary microembolization--reduced coronary reserve, microinfarction, inflammation and oxidative modification of contractile proteins, contractile dysfunction and perfusion-contraction mismatch.Furthermore, the review presents the available clinical evidence for coronary microembolization in patients and compares the clinical observations with observations in the experimental model.

Assessment of the Histological Characteristics of Coronary Arterial Plaque With Severe Calcification

BACKGROUND

Several studies have shown that rotational atherectomy (RA) is associated with higher rates of the slow-flow phenomenon and that ablated particles may be the possible cause. Intravascular ultrasound (IVUS) has an intrinsic limitation in assessing plaque morphology behind the calcification because of acoustic shadowing. Therefore, the purpose of this study was to investigate plaque characteristics behind severe calcification by histological examination.

METHODS AND RESULTS

One hundred eight coronary arterial segments from 40 human cadavers (24 males, 16 females, mean age 74+/-7 years) were examined. Serial images of IVUS were obtained and 18 severe calcified lesions were collected. Experienced observers quantitatively analyzed the lesions by computerized planimetry for fibrous, fibrofatty, calcification, and necrotic tissue area. Histologically, 15 of 18 severely calcified lesions (83%) had an extensive necrotic tissue containing large numbers of cholesterol crystals and microcalcifications; 16 of same 18 severely calcified lesions (89%) had fibrofatty tissue as well as calcification. The necrotic tissue occupied 14+/-13% and fibrofatty tissue occupied 13+/-11% of severely calcified lesions.

CONCLUSION

Necrotic core and fibrofatty tissue components "hidden" behind calcification might cause emboli-induced thrombus formation and distal flow disturbance during RA.

Rotational atherectomy in the distal left anterior descending coronary artery through an internal mammary artery graft

We report the case of a 53-year-old white man who began complaining of dyspnoea and angina 19 months after coronary artery bypass graft surgery. Coronary angiography revealed the presence of a long and critical stenosis in the native left anterior descending coronary artery, shortly after distal anastomosis of the left internal mammary artery. After failed predilatations with standard or cutting balloons, we successfully used the rotablator system, which allowed us to implant a bare-metal stent in the native left anterior descending coronary artery. However, stent deployment caused long linear graft dissection, which was reduced by drug-eluting stent implantation in the proximal and distal segments of the left internal mammary artery.

Coronary microembolization

Atherosclerotic plaque rupture is a key event in the pathogenesis of acute coronary syndromes and during coronary interventions. However, it does not always result in complete thrombotic occlusion of the entire epicardial coronary artery with subsequent acute myocardial infarction; in milder forms the result can be embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. This review summarizes the available morphological evidence for coronary microembolization in patients who died from coronary artery disease, most notably from sudden death, and then goes on to address the experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and heart failure. Finally, the review presents the available clinical evidence for coronary microembolization in patients, highlights its key features (ie, arrhythmias, contractile dysfunction, infarctlets and reduced coronary reserve) and addresses its prevention by mechanical protection devices and glycoprotein IIb/IIIa antagonism.

Effect of intracoronary nicorandil administration on preventing no-reflow/slow flow phenomenon during rotational atherectomy

A major limitation of the rotational atherectomy (RA) procedure is the occurrence of the no-reflow/slow flow phenomenon and the optimal strategy is still evolving. Recent clinical studies have demonstrated the beneficial effects of nicorandil, an adenosine triphosphate (ATP)-sensitive potassium channel opener, on no-reflow in patients with acute myocardial infarction. The purpose of this study was to evaluate the effect of nicorandil on no-reflow/slow flow phenomenon during RA procedures. Sixty-one patients who underwent RA of complex coronary lesions were randomly divided into 2 groups: (i) nicorandil cocktail (n=24 patients, 37 lesions) and (ii) verapamil cocktail (n=37 patients, 63 lesions). In each group, the drug cocktail mixed with pressurized saline was infused through the 4Fr Teflon sheath of the rotablator system during the RA procedure. In the nicorandil group, the drug cocktail consisted of 24 mg of nicorandil, 5 mg of nitroglycerin, and 10,000 U of heparin. In the verapamil group, the drug cocktail consisted of 10 mg of verapamil, 5 mg of nitroglycerin, and 10,000 U of heparin. Baseline and procedure characteristics did not differ between the 2 groups. RA was performed successfully, and death, Q-wave myocardial infarction, or emergency coronary artery bypass surgery did not occur in any patients. The no-reflow/slow flow phenomenon was observed in 11/63 (17.4%) lesions of the verapamil group, but in only 1/37 (2.7%) lesions of the nicorandil group (p=0.03). No untoward complications were observed during nicorandil infusion. These data indicate that the intracoronary continuous infusion of nicorandil during RA procedures is easy and safe, and prevents no-reflow/slow flow phenomenon more effectively than infusion of verapamil.

Coronary microembolization

Atherosclerotic plaque rupture is a key event in the pathogenesis of acute coronary syndromes and during coronary interventions. Atherosclerotic plaque rupture does not always result in complete thrombotic occlusion of the entire epicardial coronary artery with subsequent acute myocardial infarction; however, in milder forms it may result in the embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. The present report summarizes the available morphologic evidence for coronary microembolization in patients who died of coronary artery disease, especially sudden death. The report then goes on to address the experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and heart failure. Finally, the report presents the available clinical evidence for coronary microembolization, highlights its key features--arrhythmias, contractile dysfunction, infarctlets and reduced coronary reserve--and addresses prevention by mechanical protection devices and glycoprotein IIb/IIIa antagonism.

Coronary angioplasty and Rotablator atherectomy trial (CARAT): immediate and late results of a prospective multicenter randomized trial

Mechanical rotational atherectomy with the Rotablator is widely used for percutaneous coronary revascularization, but the ideal debulking strategy remains unknown. The purpose of this study was to compare the immediate and late results after Rotablator using two treatment strategies: Large burrs (burr/artery ratio of >0.7) to achieve maximal debulking (lesion debulking strategy) or small burrs (burr/artery ratio < or = 0.7) to modify lesion compliance (lesion modification strategy). Two hundred twenty-two patients at six centers were prospectively enrolled in this study and randomly assigned to large (n = 104 patients with 118 lesions) or small (n = 118 patients with 136 lesions) burrs. The primary endpoint was final diameter stenosis at the end of the procedure, and secondary endpoints included inhospital angiographic and clinical complications, and target lesion revascularization at 6 months. Baseline demographic and angiographic characteristics were similar. There were no differences in procedural success, the extent of immediate lumen enlargement, inhospital ischemic complications, or late target vessel revascularization. However, compared with small burrs, patients randomized to large burrs were more likely to experience serious angiographic complications (5.1% vs. 12.7%, P < 0.05) immediately after atherectomy. This study suggests that a routine lesion modification strategy employing small burrs (burr/artery ratio < or = 0.7) achieves similar immediate lumen enlargement and late target vessel revascularization compared with a more aggressive debulking strategy (burr/artery ratio >0.7), but with fewer angiographic complications.

Use of fractional flow reserve in the treatment of a calcific bifurcation left anterior descending coronary stenosis with rotational atherectomy

We report the results of an intervention in a high-risk surgical patient undergoing rotational atherectomy in a bifurcating lesion. The use of fractional flow reserve (FFR) was especially helpful due to the inability to visualize clearly the angiographic anatomy both before and following intervention.

Angiographic and clinical outcome of mild to moderate nonocclusive unstented coronary artery dissection and the influence on coronary flow velocity reserve. The Debate I Study Group

Limited data are available regarding the angiographic healing rate and physiologic impact of coronary artery dissections. Therefore, we studied the impact of coronary dissections on coronary flow velocity and outcome as well as their healing rate at 6-month follow-up balloon angioplasty. Of 297 patients who underwent balloon angioplasty, 225 underwent intracoronary Doppler measurements and 184 had Doppler and angiographic assessment at 6-month follow-up. Dissections were scored by an independent core lab (Cardialysis BV) and divided in 4 groups: mild (types A to B), moderate (type C), severe (D to F), and patients without dissections. Severe dissections (types D to F) were excluded from the analysis. Clinical, angiographic, and Doppler data were compared among the remaining 3 patient groups. From the 67 dissections detected after balloon angioplasty, only 3 (4.5%) remained unhealed at follow-up. Immediately after balloon angioplasty, the moderate dissection group was associated with a lower coronary flow velocity reserve than the patients with mild (2.16 +/- 0.60 vs 2.82 +/- 1.00, p = 0.037) or no dissections (2.16 +/- 0.60 vs 2.71 +/- 0.88, p = 0.046), respectively. In addition, higher recurrence of angina at 30 days was observed in the moderate group rather than in the mild group (5 [50%] vs 8 [16%], p = 0.0160) and in the patients without dissections (11 [12%], p = 0.007). After standard balloon angioplasty, the occurrence of unhealed dissections is a rare phenomenon. An impaired coronary flow reserve was observed after the development of nonocclusive type C dissections, which was associated with a worse short-term outcome.

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.

Novel approach to rotational atherectomy results in low restenosis rates in long, calcified lesions: long-term results of the San Antonio Rotablator Study (SARS)

Ablation technique and adjunctive strategy may affect restenosis after rotational atherectomy. To minimize trauma to the vascular wall, we changed the technique of rotablation as follows: the RPM range was decreased to 140,000-160,000 RPM, the ablation was performed using a repetitive pecking motion, avoiding a decrease in the rotational speed of the burr greater than 3,000 RPM, long lesions were divided into segments and each segment was separately ablated, and the burr-to-artery ratio was intended to be approximately 0.75. To prevent coronary spasm, before and after each pass, 100-200 microg nitroglycerin and 100-200 microg verapamil i.c. boluses were administered. Adjunctive PTCA was performed using a closely sized 1.1:1 balloon-to-artery ratio with a noncompliant balloon at low pressures for 120 sec. The study incorporated 111 patients with a combined total of 146 calcified lesions. Results. A total of 31.5% of patients underwent a multivessel procedure. No deaths occurred. Q-wave MI and/or creatine kinase elevation greater than three times baseline levels occurred in 4.5% of patients. By quantitative coronary angiography (QCA), the reference vessel diameter was 3.13+/-0.59 mm, mean lesion length was 33.41+/-18.58 mm. Percent stenosis and mean luminal diameter were as follows: at baseline 75.7%+/-10.8%, or 0.76+/-0.41mm, Post-rotational atherectomy 41.5%+/-3.6%, or 1.83+/-0.43 mm, Post-PTCA 18.2%+/-11.9%, or 2.56+/-0.50 mm. Six-month angiographic follow-up was available in 64 (57.7%) pts. Net luminal gain was 1.15+/-0.76 mm, with a late luminal loss of 0.65+/-0.84 mm. The mean diameter stenosis at follow-up was 37.6%+/-28.5%, with MLD 1.91+/-1.21 mm. The binary restenosis rate was 28.1%. Therefore, modification of rotational atherectomy technique with adjunctive PTCA resulted in a favorable restenosis rate in long, calcified lesions. Cathet. Cardiovasc. Intervent. 48:48-53, 1999.

Anaesthesia care and the adult cardiac catheterization patient

The number and types of procedures being performed in the adult cardiac catheterization suite have increased dramatically, with an aggressive move towards percutaneous interventional cardiac procedures. Here we review many of these procedures, including the current trends in North America and Europe. Coronary angioplasty is now more commonly performed than coronary artery bypass grafting. The past 5 years have seen a proliferation of coronary stenting procedures. Restenosis of coronary arteries continues to be a major area of research and concern.