Detection of coronary microembolisation by Doppler ultrasound during percutaneous coronary interventions

Ischemic Heart Disease Pathophysiology Paradigms Overview: From Plaque Activation to Microvascular Dysfunction

Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.

A systematic review and meta-analysis evaluating ischemic conditioning during percutaneous coronary intervention

AIM

A systematic review and meta-analysis, evaluating ischemic conditioning during percutaneous coronary intervention (PCI).

METHODS & RESULTS

A database search of randomized trials of ischemic conditioning in PCI created three subgroups for meta-analysis: mortality in elective PCI with remote ischemic preconditioning (RIPreC; subgroup 1a, n = 3) - no outcome difference between RIPreC and control (odds ratio: 0.34; 95% CI: 0.08-1.56), myocardial salvage index in ST-elevation myocardial infarction (STEMI) with RIPreC (subgroup 1b, n = 2) - favored RIPreC (mean difference: 0.13; 95% CI: 0.07-0.19), and infarct size in STEMI with local ischemic postconditioning (LIPostC) (subgroup 4b, n = 12) - favored LIPostC (mean difference: -4.13 g.m^-2; 95% CI: -7.36 to -0.90 g.m^-2).

CONCLUSION

RIPreC and LIPostC improve myocardial salvage index and myocardial infarct size respectively in PCI for STEMI. No mortality benefit detected with RIPreC in elective PCI.

Remote Ischemic Conditioning in Elective PCI?

This review examines the rationale for using remote ischemic conditioning (RIC) in elective percutaneous coronary intervention (PCI) to prevent procedure-related ischemia-reperfusion injury and justifies the importance of periprocedural biomarker elevation following elective PCI as a valid target for RIC. We review the evidence for the use of RIC as a treatment in this setting and document the salutary rules that must be followed to successfully translate RIC for clinical benefit.

Cardioprotective Effects of Atorvastatin plus Trimetazidine in Percutaneous Coronary Intervention

Objective: To explore the effects of preoperative administration of conventional doses of atorvastatin plus trimetazidine on the myocardial injury of patients during the perioperative period of percutaneous coronary intervention (PCI).

Methodology: 475 cases of acute coronary syndrome patients before PCI were randomly divided into the control group (238 cases) and experimental group (237 cases).The control group was treated with conventional doses of atorvastatin calcium (20 mg each time, once a night), and the experimental group was treated with conventional doses of atorvastatin calcium plus trimetazidine hydrochloride (20 mg each time, tid) for 3 d. After PCI, preoperative and postoperative 24 h concentrations of serum creatine kinase MB isoenzyme (CK-MB), cardiac troponin I (cTnI) and high sensitivity C-reactive protein (hs-CRP) as well as activity of myeloperoxidase (MPO) were investigated. Left ventricular ejection fractions of the patients were then examined 4 weeks later.

Results: Postoperative 24 h cTnI concentration and elevated MPO activity of the experimental group were significantly lower than those of the control group (P <0 05). CK-MB activities and hs-CRP concentrations of the two groups did not differ significantly (P> 0 05).

Conclusion: The administration of conventional doses of atorvastatin plus trimetazidine three days before PCI is able to protect the perioperative patients from myocardial injury.

Spontaneous and procedural plaque embolisation in native coronary arteries: pathophysiology, diagnosis, and prevention

The detachment of atherothrombotic material from the atherosclerotic coronary plaque and downstream embolisation is an underrecognized phenomenon and it causes different degrees of impairment of the coronary microcirculation. During treatment of obstructive atherosclerotic plaque by percutaneous coronary intervention (PCI) distal embolisation (DE) is considered to be inevitable and it is associated with potential clinical and prognostic implications. This review aims to assess the main aspects of both spontaneous and procedural DE, analyze their different pathophysiology, provide specific insights on the main diagnostic tools for their identification, and finally focus on the main strategies for their treatment and prevention.

Effect of remote ischemic preconditioning in the elderly patients with coronary artery disease with diabetes mellitus undergoing elective drug-eluting stent implantation

There is conflicting evidence regarding the effectiveness of remote ischemic preconditioning (RIPC) in patients undergoing elective percutaneous coronary intervention (PCI). Therefore, we prospectively enrolled elderly patients with coronary heart disease (CHD) with diabetes mellitus (DM) undergoing elective drug-eluting stent (DES) implantation. They were randomized to receive RIPC within 2 hours before PCI (n = 102) or not (controls, n = 98). Baseline clinical characteristics were similar between the 2 groups. Despite a trend toward decline, the median high-sensitivity cardiac troponin I (hscTnI) level (P = .256) and the incidence of myocardial infarction (MI) type 4a (P = .106) in the RIPC group 16 hours after PCI procedure was not significantly different from the control group. The RIPC could attenuate the release of a myocardial biomarker but failed to show a significant effect on hscTnI level or MI type 4a incidence after PCI procedure in elderly patients with CHD having DM undergoing elective DES implantation.

Effect of remote ischemic preconditioning on serum troponin T level following elective percutaneous coronary intervention

BACKGROUND

Elective percutaneous coronary intervention (PCI) is associated with myocardial necrosis, as evidenced by troponin release, in approximately one-third of cases. This is known to be linked with subsequent cardiovascular events. This study assessed the ability of remote ischemic preconditioning (RIPC) to attenuate cardiac troponin T (cTnT) release after elective PCI.

OBJECTIVE

Evaluation of effect of RIPC on myocardial markers following elective PCI.

METHODS

One hundred and forty nine consecutive patients undergoing elective PCI with undetectable preprocedural cTnT were recruited. Subjects were randomized to receive RIPC (induced by three 5-min inflations of a blood pressure cuff to 200 mm Hg around the upper arm, followed by 5-min intervals of reperfusion) or control (cuff deflated) immediately before arrival in the cardiac catheterization room. The primary outcome was cTnT level at approximately 16 hr after PCI. Secondary outcomes included occurrence of postprocedural myocardial infarction (MI), CKMB levels at 16 hr after PCI and assessment of the inflammatory response as measured by C-reactive protein (CRP) levels.

RESULTS

The mean cTnT at 16 hr after PCI was lower in the RIPC group compared with the control group. (0.020 vs. 0.047 ng/ml; P = 0.047) Occurrence of postprocedural MI, CKMB and CRP levels did not differ in both groups (P = 0.097, 0.537, and 0.481 respectively).

CONCLUSION

The use of RIPC immediately prior to PCI attenuates procedure-related cTnT release and does not affect occurrence of post procedural MI, CKMB, or CRP levels.

Remote ischemic preconditioning reduces myocardial injury in patients undergoing coronary stent implantation

BACKGROUND

Myocardial necrosis occurs frequently in elective percutaneous coronary intervention (PCI) and is associated with subsequent major adverse cardiovascular events (MACEs). This study assessed the protective effect of remote ischemic preconditioning (RIPC) in patients undergoing successful drug-eluting stent implantation with normal baseline troponin values.

METHODS

We analyzed 205 participants with normal baseline troponin values undergoing successful coronary stent implantation. Subjects were randomized to 2 groups: The RIPC group (n = 101), whose members received RIPC (created by three 5-minute inflations of a pneumatic medical tourniquet cuff to 200 mm Hg around the upper arm, interspersed with 5-minute intervals of reperfusion) < 2 hours before the PCI procedure, and the control group (n = 104).

RESULTS

The primary outcomes were high sensitive cardiac troponin I (hscTnI) levels and incidence of myocardial infarction (MI 4a, defined as hscTnI > 0.20 ng/mL) at 16 hours after the PCI procedure. The median hscTnI at 16 hours after PCI was lower in the RIPC group compared with the unpreconditioned, control group (0.11 vs 0.21 ng/mL; P < 0.01). The incidence of MI 4a was lower in the RIPC group compared with the control group (39% vs 54%, P < 0.05). Index of renal function showed no difference between the 2 groups at 16 hours after PCI (P > 0.05).

CONCLUSION

RIPC reduced post-PCI TnI release and incidence of MI 4a in patients undergoing elective coronary stent implantation.

Detection of coronary microembolization by Doppler ultrasound in patients with stable angina pectoris during percutaneous coronary interventions under an adjunctive antithrombotic therapy with abciximab: design and rationale of the High Intensity Transient Signals ReoPro (HITS-RP) study

Background

Embolization of atherosclerotic debris from the rupture of a vulnerable atherosclerotic plaque occurs iatrogenically during percutaneous coronary interventions (PCI) and can induce myocardial necrosis. These microembolizations are detected as high intensity transient signals (HITS) using intracoronary Doppler technology.

Presentation of the hypothesis

In the presented study we will test if abciximab (ReoPro®) infusion reduces high intensity transient signals in patients with stable angina pectoris undergoing PCI in comparison to standard therapy alone.

Testing the hypothesis

The High Intensity Transient Signals ReoPro® (HITS-RP) study will enroll 60 patients. It is a prospective, single center, randomized, double-blinded, controlled trial. The study is designed to compare the efficacy of intravenous abciximab administration for reduction of microembolization during elective PCI. Patients will be randomized in a 1:1 fashion to abciximab or placebo infusion. The primary end point of the HITS-RP-Study is the number of HITS during PCI measured by intracoronary Doppler wire. Secondary endpoints are bleeding complications, elevation of cardiac biomarkers or ECG changes after percutaneous coronary interventions, changes in coronary flow velocity reserve, hs-CRP elevation, any major adverse cardio-vascular event during one month follow-up.

Implications of the hypothesis

The HITS-RP-Study addresses important questions regarding the efficacy of intravenous abciximab administration in reducing microembolization and periprocedural complications in stable angina pectoris patients undergoing PCI.

Trial registration

The trial is registered under http://www.drks-neu.uniklinik-freiburg.de/drks_web/:DRKS00000603.

Deep echo attenuation without calcification increases the risk of periprocedural myonecrosis after elective percutaneous coronary intervention in patients with coronary artery disease

OBJECTIVE

To investigate the clinical factors, including intravascular ultrasound (IVUS) findings, associated with percutaneous coronary intervention (PCI)-related periprocedural myonecrosis (PM) in patients with stable coronary artery disease (CAD).

METHODS

The study included 46 patients (mean age 65±2 y, 37 men) with stable CAD who underwent elective PCI using IVUS and a Doppler flow guidewire. In addition to routine IVUS measurements, the presence of deep echo attenuation (DEA) without calcification was assessed. The sum of all high-intensity transient signals (HITS) after a balloon deflation procedure was calculated using a Doppler flow guidewire. PM was defined as an elevation in troponin T to >0.03 ng/mL 24-hour after PCI. Patients were divided into 2 groups on the basis of the presence or absence of PM.

RESULTS

PM was identified in 17 patients (37%). Estimated glomerular filtration ratio was lower in the PM group (p=0.021). Target vessel distribution was different between the groups (p=0.004). Positive remodeling and DEA, as observed on IVUS, were more common in the PM group (p=0.03 and p<0.0001, respectively). The total number of HITS was higher in the PM group (p=0.003). Logistic regression analysis demonstrated that the presence of DEA (p=0.003) was the sole factor associated with the occurrence of PM.

CONCLUSION

These results demonstrated that DEA is an important factor associated with PM in patients who underwent an elective PCI. Therefore, IVUS to determine the presence of DEA should be performed before PCI.

Establishment and characterization of an experimental model of coronary thrombotic microembolism in rats

To establish a model of coronary thrombotic microembolism in rats, either automicrothrombotic particulates (CM group) or saline control (SHAM group) was injected into temporarily clamped aortas of male Sprague-Dawley rats. After automicrothrombotic particulate injection, serum c-troponin I and von Willebrand factor levels, the no-flow area as evaluated by Thioflavin S, myocardial leukocyte infiltration levels, myocardial expressions of tumor necrosis factor alpha and interleukin-6, the percentage of arterioles obstructed by thrombosis, and myocardial fibrosis were all significantly increased whereas cardiac function as evaluated by echocardiography and hemodynamic measurements were significantly reduced compared with the sham group. Thus, aortic automicrothrombotic particulate injection could induce coronary microembolism in rats, and this model could be of value in improving the understanding of pathophysiology of coronary microembolism.

Cardiac Remote Ischemic Preconditioning in Coronary Stenting (CRISP Stent) Study: a prospective, randomized control trial

BACKGROUND

Myocyte necrosis as a result of elective percutaneous coronary intervention (PCI) occurs in approximately one third of cases and is associated with subsequent cardiovascular events. This study assessed the ability of remote ischemic preconditioning (IPC) to attenuate cardiac troponin I (cTnI) release after elective PCI.

METHODS AND RESULTS

Two hundred forty-two consecutive patients undergoing elective PCI with undetectable preprocedural cTnI were recruited. Subjects were randomized to receive remote IPC (induced by three 5-minute inflations of a blood pressure cuff to 200 mm Hg around the upper arm, followed by 5-minute intervals of reperfusion) or control (an uninflated cuff around the arm) before arrival in the catheter laboratory. The primary outcome was cTnI at 24 hours after PCI. Secondary outcomes included renal dysfunction and major adverse cardiac and cerebral event rate at 6 months. The median cTnI at 24 hours after PCI was lower in the remote IPC compared with the control group (0.06 versus 0.16 ng/mL; P=0.040). After remote IPC, cTnI was <0.04 ng/mL in 44 patients (42%) compared with 24 in the control group (24%; P=0.01). Subjects who received remote IPC experienced less chest discomfort (P=0.0006) and ECG ST-segment deviation (P=0.005) than control subjects. At 6 months, the major adverse cardiac and cerebral event rate was lower in the remote IPC group (4 versus 13 events; P=0.018).

CONCLUSIONS

Remote IPC reduces ischemic chest discomfort during PCI, attenuates procedure-related cTnI release, and appears to reduce subsequent cardiovascular events.

Automatic Detection of Microemboli During Percutaneous Coronary Interventions

The objective of this study was to develop an analysis method for the automatic detection of intracoronary microemboli triggered high intensity signals (HITS) during percutaneous coronary interventions (PCI). The recorded ultrasonic Doppler velocity spectra from an intracoronary ultrasonic guide-wire were decomposed into 13 wavelet scales applying the continuous wavelet transform. From 7 wavelet scales which were most suitable for a differentiation between HITS and pulsatile flow, envelopes were calculated and combined to improve the HITS-to-background noise ratio. For different intensity thresholds the resulting number of HITS was automatically counted and compared with the number estimated by experienced observers. In a first validation trial HITS were detected within a simplified in vitro model with a sensitivity of 89.2% and a positive predictive value of 87.6%. In a following clinical study 211 HITS from 18 patients during PCI were counted manually by the observers. With the developed wavelet-based method 189 HITS were correctly detected (sensitivity of 89.6%, positive predictive value of 85.5%). The introduced new method automatically detects intracoronary HITS for the first time with a reliable accuracy. This may support further studies evaluating the incidence and consequences of coronary microembolization during coronary interventions.

Detection of Coronary Microembolization by Doppler Ultrasound in Patients With Stable Angina Pectoris Undergoing Elective Percutaneous Coronary Interventions

Background— Intracoronary Doppler guidewires can be used for real-time detection and quantification of microembolism during percutaneous coronary interventions (PCIs). We investigated whether the frequency of Doppler-detected microembolism is related to the incidence of myonecrosis during elective PCI.

Methods and Results— The study population included 52 consecutive patients (aged 64±10 years; 36 men, 16 women) with coronary artery disease who underwent elective PCI of a single-vessel stenosis. Using intracoronary Doppler ultrasound, we compared the frequency of microembolism during PCI in 22 patients with periprocedural non–ST-segment elevation myocardial infarctions (pNSTEMI) and 30 patients without pNSTEMI. The 2 groups were comparable with regard to their clinical and procedural characteristics. In the group with pNSTEMI, the total number of coronary microemboli after PCI (27±10 versus 16±8, P <0.001) was higher than in the group without pNSTEMI. Although high-sensitivity C-reactive protein plasma levels were similar before PCI (2.9±2.2 versus 3.4±1.7 mg/L, P =NS), they were higher in the group with pNSTEMI after PCI (12.6±10.4 versus 6.1±5.1 mg/L, P <0.05). Microembolic count independently correlated to postprocedural cardiac troponin I elevation ( r =0.565, P <0.001), coronary flow velocity reserve ( r =−0.506, P <0.001), and baseline average peak velocity ( r =0.499, P <0.001).

Conclusions— Patients with pNSTEMI had a significantly higher frequency of coronary microembolization during PCI, and their systemic inflammatory response and microvascular impairment after PCI were more pronounced. Intracoronary Doppler ultrasound provides evidence that pNSTEMI in patients undergoing elective PCI is caused by microembolization during the procedure.

Detection and quantification of embolic particles during percutaneous coronary intervention to stable plaque: It correlates to coronary flow dynamics and myocardial damage

OBJECTIVES

We detected embolic particles liberated from plaque during percutaneous coronary intervention (PCI) as high-intensity transient signals (HITS) with a Doppler guidewire and studied their impact on coronary flow dynamics and the myocardium in patients with stable angina pectoris.

BACKGROUND

These embolic particles during PCI may cause myocardial injury. However, this was difficult to confirm because it was impossible to detect embolic particles.

METHODS

We performed balloon angioplasty followed by stenting in 31 patients while monitoring coronary flow velocity. After PCI, we measured average peak velocity at baseline and after infusion of adenosine 5'-triphosphate to calculate coronary flow velocity reserve (CFVR) and coronary resistance index (CRI). In patients with PCI to the left coronary artery (n = 21), we calculated relative CFVR as the ratio of CFVR in the target vessel to that in the reference vessel. We measured cardiac troponin T (cTnT) the day after PCI.

RESULTS

HITS were detected in 27 (87%) of 31 patients and the majority were observed after stenting. The total number of HITS was correlated with CRI (r = 0.36, P = 0.049) or relative CFVR (r = 0.65, P = 0.0036) but not with CFVR (r = 0.048, P = 0.82). Thirteen patients showed elevated cTnT (range, 0.05-0.31 ng/ml) and the total number of HITS was greater in those with elevated cTnT than in those without elevated cTnT (24 +/- 9 vs. 10 +/- 7, P = 0.0007).

CONCLUSIONS

Embolic particles are frequently observed during PCI to stable plaque and the majority are liberated after stenting. There appears to be a quantitative relationship between amounts of HITS and coronary microvessel dysfunction and minor myocardial injury.