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.

Impact on adenosine stress cardiac magnetic resonance for recanalisation and follow up of chronic total coronary occlusions

OBJECTIVE

To evaluate the impact on cardiac magnetic resonance imaging (CMRI) with adenosine stress and delayed enhancement for indication and follow up after interventional recanalisation of chronic total coronary occlusions (CTOs).

MATERIAL AND METHODS

Twenty consecutive patients (15 males; 5 females; mean age 65 years) with CTO verified by cardiac catheterisation referred to CMRI. Sixteen of them got CMRI before and after coronary recanalisation. Wall motion abnormalities (WMAs), first pass perfusion with adenosine and viability were assessed using a 1.5 T MR scanner (Sonata; Siemens). CMRI results were compared with clinical classifications, the results of cardiac catheterisation and follow up angiography.

RESULTS

Sixteen patients had a successful recanalisation, 15 of the occluded coronary artery and one of collateral donor artery stenosis. After recanalisation all stress-induced progressive or new wall motion abnormalities (WMAs) of the corresponding segments and in the collateral donor territory (5 patients) and all adenosine induced perfusion defects (PD) or delay (12 patients) were regredient. 13/16 patients showed no transmural and one patient transmural delayed enhancement (DE) indicating myocardial scar. In 10/16 patients CSS grading of angina improved after recanalisation.

CONCLUSION

After successful recanalisation of CTOs, patients with preinterventional stress-induced PDs and WMAs in viable myocardium did not display any signs of stress-induced ischemia postinterventionally. A comprehensive CMRI approach, including assessment of rest and stress WMAs, first pass perfusion and myocardial viability represents an important tool for the pre-interventional decision to recanalise CTOs and follow up.

Improvement of the primary success rate of recanalization of chronic total coronary occlusions with the Safe-Cross system after failed conventional wire attempts

BACKGROUND

In view of the improved long-term patency with drug-eluting stents, the challenge with chronic total coronary occlusion (CTO) remains the low primary success rate. Improved guide wires have increased this rate, but alternative devices may be of additional value. The goal of the present study was to determine the additional benefit of a new penetration device in CTOs after an extensive conventional wire approach.

METHODS AND RESULTS

In 148 consecutive patients the recanalization of a CTO of >3 months was attempted. A conventional wire approach was used with recent dedicated recanalization wires, which was successful in 104 patients (70%). If after at least 20 min of fluoroscopic time no crossing of the wire was achieved, the Safe-Cross wire (SC) (Intralumina) was used which enables verification of the intraluminal wire position via optical reflectometry, and crossing of resistent occlusion caps by radiofrequency ablation. Due to severe dissections after the conventional approach, the SC was not used in 10 patients. In 34 patients the SC wire was applied, leading to successful lesion crossing in 14 patients (41%). Thus, the primary success rate was improved from 70.2% to 79.7%. No periprocedural major adverse events were observed with the SC wire. The successful attempts with the SC wire were predominantly in blunt occlusions. All patients with successful wire passage could be treated with one or more stents.

CONCLUSIONS

In a real world cohort of patients with CTO, the SC wire could increase the primary success rate after failed extensive conventional wire attempt. In these worst case patients the SC success rate was 41%. This new wire appears to have additional potential in failures of a conventional wire approach.

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.

Treatment with granulocyte-colony stimulating factor in patients with acute myocardial infarction. Evidence for a stimulation of neovascularization and improvement of myocardial perfusion

BACKGROUND

Stem cell therapy has been suggested to be beneficial in patients after acute myocardial infarction (AMI). Strategies of treatment are either a local application of mononuclear bone marrow cells (BMCs) into the infarct-related artery or a systemic therapy with the granulocyte-stimulating factor (G-CSF) to mobilize BMCs. Nevertheless, the mechanisms responsible for improvement of cardiac function and perfusion are speculative at present. This study has been performed to investigate the effect of G-CSF on systemic levels of vascular growth factors and chemokines responsible for neovascularization, that might help to understand the positive effects of a G-CSF therapy after AMI.

METHODS AND RESULTS

Five patients in the treatment group and 5 patients in the control group were enrolled in this study. The patients in the treatment group received 10 microg/kg bodyweight/day of G-CSF subcutaneously for a mean treatment duration of 6.6 +/- 1.1 days. In both groups, levels of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and monocyte chemotactic protein-1 (MCP-1) were measured on day 2 to 3 and day 5 after AMI. The regional wall perfusion and the ejection fraction (EF) were evaluated before discharge and after 3 months with ECG-gated MIBI-SPECT and radionuclide ventriculography, respectively. Significant higher levels of VEGF (p < 0.01), bFGF (p < 0.05) and MCP-1 (p < 0.05) were found in the treatment group compared to the control group. Levels of VEGF and bFGF remained on a plateau during the G-CSF treatment and decreased significantly in the control group. The wall perfusion improved significantly within the treatment group and between the groups (p < 0.05), respectively. The EF improved significantly within the treatment group (p < 0.05), but the change of the EF between the groups was not significant.

CONCLUSION

In patients with AMI, the treatment with G-CSF modulates the formation of vascular growth factors that might improve neovascularization and result in an improved myocardial perfusion and function.

The functional reserve of collaterals supplying long-term chronic total coronary occlusions in patients without prior myocardial infarction

AIMS

Chronic total coronary occlusions (CTOs) with angiographically well-developed collaterals may be considered to provide sufficient blood supply to the occluded segment, and the indication for revascularization may be questioned. Therefore, the collateral function and functional reserve in patients with a CTO without a prior Q-wave myocardial infarction (MI) were assessed.

METHODS AND RESULTS

Invasive assessment of collateral function was done during successful percutaneous coronary intervention in 107 patients with a CTO and no prior Q-wave MI. Intracoronary Doppler flow velocity and pressure recordings were obtained distal to the occlusion before the first balloon inflation and collateral function indexes calculated. In 62 patients, additional pharmacological stress testing was done by intravenous adenosine (140 microg/kg/min) to assess the collateral flow reserve. Patients with normal and impaired regional dysfunction were compared. Collateral function was similar in patients with and without regional left ventricular (LV) dysfunction. In both groups, 78% collaterals provided a collateral pressure index at baseline > 0.3, sufficient to prevent ischaemia during a balloon occlusion, with a minimum of 0.2 in those with preserved LV function. A Doppler-derived function index showed a wider variation due to the high prevalence of microvascular dysfunction in CTOs. Only 7% of patients had an increase in collateral flow reserve > 2.0 during pharmacological stress, whereas coronary steal occurred in one-third independent of regional LV function.

CONCLUSION

A limited increase in collateral flow and the high prevalence of coronary steal during stress underscore the functional limitation of collaterals in CTOs without prior Q-wave MI. Even presumably 'well-collateralized' CTOs may benefit from a revascularization.

Low incidence of cardiac biomarker elevation following PCI of chronic total coronary occlusions

BACKGROUND AND OBJECTIVES

After a percutaneous coronary intervention (PCI) creatine kinase-MB fraction (CK-MB) elevation is observed in 5 to 30% of the cases. The often long and diffuse lesions of chronic total coronary occlusions (CTO) could represent a high risk group. However, there is no systematic data available on the incidence of elevation of cardiac troponin I (cTNI) after recanalisation of CTOs.

METHODS

In 201 patients a CTO was successfully recanalised with stenting of all lesions and the regional wall motion (WMSI) was assessed at baseline and follow-up. For comparison we analysed 111 stable angina patients with stenting of single non-occlusive lesions. Over a period of 24 hours after PCI, CK-MB and cTNI were measured.

RESULTS

CK-MB elevation after recanalisation of CTOs was observed in only 6% of patients with CTOs. The incidence of cardiac biomarker elevation was similar in patients with normal and severely impaired regional function, indicating that the low incidence was not due to a high prevalence of non-vital myocardium. In comparison CK-MB elevation after stenting of single non-occlusive lesions was observed in 13% of patients. In 14% of patients with CTOs and in 20% of patients with a single non-occlusive lesions cTNI increased after PCI.

CONCLUSIONS

Despite the high plaque load of organised thrombotic material in CTOs, the incidence of cardiac biomarker elevation after recanalisation of CTOs was similar to that after stenting of single non-occlusive lesions. A specific adjunctive medical or interventional therapy may not be warranted during recanalisation of CTOs.

Determinants of coronary steal in chronic total coronary occlusions donor artery, collateral, and microvascular resistance

OBJECTIVES

We aimed to assess the mechanisms of coronary steal by direct hemodynamic measurements of the collateral circulation in chronic total coronary occlusions (CTO).

BACKGROUND

Coronary steal may cause ischemia despite well-developed collaterals in coronary artery disease.

METHODS

Fifty-six patients were studied during recanalization of a CTO. Before recanalization, the fractional flow reserve in the donor artery (FFR(D)) at the takeoff of the collaterals and the coronary flow reserve were recorded. After crossing the occlusion, the distal coronary flow velocity was measured by a Doppler wire (APV(Occl)), and distal pressure by a pressure wire. Changes of these parameters were assessed during intravenous adenosine (140 microg/kg/min). Resistance indexes for the donor artery (R(D)), collaterals (R(C)), and microcirculation (R(P)) were calculated.

RESULTS

Adenosine caused a decrease of APV(Occl) (i.e., coronary steal, in 26 patients [group S], an increase in 19 patients [group R], and no change in 11 patients). The FFR(D) was lower in group S. R(D) and R(C) increased in group S, while R(D) did not change significantly and R(C) decreased in group R. Patients with steal had more severe regional dysfunction. Patients with steal but without an FFR(D) <0.8 tended to have an impaired microvascular function.

CONCLUSIONS

We could demonstrate that coronary steal in man is mainly due to a hemodynamically significant donor artery lesion, but can also occur due to an impaired vasodilatory reserve of the microcirculation in the absence of a donor artery lesion. Coronary steal may have an adverse influence on the preservation of myocardial function by collaterals.

Analysis of Location and Pattern of Target Vessel Failure in Chronic Total Occlusions after Stent Implantation and Its Potential for the Efficient Use of Drug-Eluting Stents

OBJECTIVES

The recanalization of chronic total occlusions (CTOs) is a complex procedure with high rates of target vessel failure (TVF), i.e., restenosis or reocclusion. Little is known about the localization of lesion recurrence, and whether extensive stenting should be performed. In this prospective analysis, the area at high risk for restenoses after recanalization of CTO was localized.

METHODS

Angiograms of 97 consecutive patients and control angiograms after a mean period of 5 +/- 1.3 months were analyzed for location and length of the CTO and the sites of recurrences.

RESULTS

In total, 158 stents were implanted (1.6 +/- 0.9 per lesion). Restenoses occurred in 39% and reocclusions in 17% of the patients. Patients with a TVF had a longer CTO than patients without TVF (17.9 +/- 10.2 vs 13.9 +/- 8.6 mm; P = 0.023). The TVF rate increased with the number of implanted stents. The stent diameter was smaller in lesions with subsequent reocclusions than in restenotic and nonrestenotic lesions (2.8 +/- 0.5 vs 3.0 +/- 0.4 and 3.2 +/- 0.4 mm resp.; P = 0.007). Analyzing the localization of the 38 restenoses, we only found 45% restricted to the area of the former CTO, while 82% were located in the area of the former CTO plus 10 mm in proximal and distal direction.

CONCLUSIONS

Stents should not only cover the site of the CTO, but should enclose the high-risk area of recurrence within 10 mm proximal and distal of the former CTO. This may guide the rational use of drug-eluting stents.

Turbulent flow as a cause for underestimating coronary flow reserve measured by Doppler guide wire

Background

Doppler-tipped coronary guide-wires (FW) are well-established tools in interventional cardiology to quantitatively analyze coronary blood flow. Doppler wires are used to measure the coronary flow velocity reserve (CFVR). The CFVR remains reduced in some patients despite anatomically successful coronary angioplasty. It was the aim of our study to test the influence of changes in flow profile on the validity of intra-coronary Doppler flow velocity measurements in vitro. It is still unclear whether turbulent flow in coronary arteries is of importance for physiologic studies in vivo.

Methods

We perfused glass pipes of defined inner diameters (1.5 – 5.5 mm) with heparinized blood in a pulsatile flow model. Laminar and turbulent flow profiles were achieved by varying the flow velocity. The average peak velocity (APV) was recorded using 0.014 inch FW. Flow velocity measurements were also performed in 75 patients during coronary angiography. Coronary hyperemia was induced by intra-coronary injection of adenosine. The APV maximum was taken for further analysis. The mean luminal diameter of the coronary artery at the region of flow velocity measurement was calculated by quantitative angiography in two orthogonal planes.

Results

In vitro, the measured APV multiplied with the luminal area revealed a significant correlation to the given perfusion volumes in all diameters under laminar flow conditions (r² > 0.85). Above a critical Reynolds number of 500 – indicating turbulent flow – the volume calculation derived by FW velocity measurement underestimated the actual rate of perfusion by up to 22.5 % (13 ± 4.6 %). In vivo, the hyperemic APV was measured irrespectively of the inherent deviation towards lower velocities. In 15 of 75 patients (20%) the maximum APV exceeded the velocity of the critical Reynolds number determined by the in vitro experiments.

Conclusion

Doppler guide wires are a valid tool for exact measurement of coronary flow velocity below a critical Reynolds number of 500. Reaching a coronary flow velocity above the velocity of the critical Reynolds number may result in an underestimation of the CFVR caused by turbulent flow. This underestimation of the flow velocity may reach up to 22.5 % compared to the actual volumetric flow. Cardiologists should consider this phenomena in at least 20 % of patients when measuring CFVR for clinical decision making.

Resting 12-lead electrocardiogram as a reliable predictor of functional recovery after recanalization of chronic total coronary occlusions

BACKGROUND

A major goal of revascularization is the recovery of left ventricular (LV) function. Nuclear imaging techniques are widely used for detecting recovery of function with a good sensitivity, but only moderate specificity. Predictors of recovery in chronic total coronary occlusions (CTO) are not investigated.

HYPOTHESIS

The 12-lead-resting electrocardiogram (ECG) is a predictor of LV recovery after successful recanalization of CTO.

METHODS

Successful recanalization of CTO was performed in 127 patients. Of these, 62 patients, who constitute the study group, had impaired regional wall motion prior to recanalization. The 12-lead resting ECG was evaluated for Q-wave areas and parameters of QT dispersion. Impairment of regional wall motion was evaluated by LV angiogram at baseline and at follow-up.

RESULTS

Angiographic follow-up after 5 +/- 1.4 months documented reocclusion in eight patients. Complete follow-up with a patent coronary artery and an ECG without bundle-branch block was available in 43 patients. Wall motion severity index (WMSI) improved from -2.92 +/- 0.28 to -1.34 +/- 0.61 (p < 0.001) in patients without Q waves, whereas it was unchanged in patients with Q waves (-3.01 +/- 0.30 and -2.81 +/- 0.32). Absence of Q waves at baseline predicted recovery of regional wall motion with 89% sensitivity and 67% specificity. Positive predictive value for recovery was 68% in patients without Q waves, but only 11% in patients with Q waves. In multivariate analysis, only absence of Q waves predicted improvement in WMSI (p = 0.01).

CONCLUSIONS

In patients with recanalization of CTO, recovery of regional wall motion is reliably predicted by analysis of the resting 12-lead ECG for pathologic Q waves.

Detection of coronary microembolisation by Doppler ultrasound during percutaneous coronary interventions

OBJECTIVE

To validate an intracoronary Doppler ultrasound device for high intensity transient signals (HITS) detection and to assess the incidence of HITS during percutaneous coronary intervention (PCI).

METHODS AND RESULTS

In an in vitro model, particle count and number of HITS detected by an intracoronary 0.014 inch Doppler wire were closely correlated (r = 0.97, p < 0.001). In the clinical study, 32 patients (mean (SD) age 61 (11) years; 23 men, nine women) with coronary artery disease were treated with balloon dilatation and stent implantation for a single vessel stenosis. In these patients HITS were detected during PCI in 84% (27 of 32). Reproducibility (r = 0.99, p < 0.001) and interobserver agreement (r = 0.84, p < 0.001) of HITS counts were significant. The number of HITS after stent implantation was significantly higher than after balloon dilatation (11 (7) v 2 (4), p < 0.001). Postprocedural coronary flow velocity reserve (CFVR) was < 2.0 in 55% (16 of 29) of all patients after balloon dilatation and < 2.0 in 23% (six of 26) after stent implantation. The number of HITS after stent implantation did not differ significantly between patients with CFVR < 2.0 and patients with CFVR > or = 2.0 (12 (8) v 10 (7), not significant).

CONCLUSIONS

Embolic particles can be detected as HITS by an intracoronary Doppler ultrasound device. Coronary microembolism is often observed during PCI, especially after stent implantation. However, the incidence of HITS alone does not explain a reduced CFVR after PCI.

Treatment with granulocyte colony-stimulating factor for mobilization of bone marrow cells in patients with acute myocardial infarction

BACKGROUND

This study was undertaken to evaluate the hypothesis that treatment with granulocyte colony-stimulating factor (G-CSF) to mobilize bone marrow cells (BMCs) is feasible and safe and promotes neovascularization and myocardial function in patients with acute myocardial infarction.

METHODS

Fourteen patients in the treatment group and 9 patients in the control group were enrolled in this prospective, nonrandomized, open-label study. Forty-eight hours after successful recanalization and stent implantation, the patients of the treatment group received 10 microg/kg body weight per day G-CSF subcutaneously for mean treatment duration of 7.0 +/- 1.0 days. Nine patients fulfilled the entry criteria but refused participation and served therefore as control group. In both groups, regional wall motion and perfusion was evaluated with electrocardiogram-gated sestamibi single-photon emission computed tomography imaging and ejection fraction with radionuclidventriculography before discharge and after 3 months.

RESULTS

No severe side effects of G-CSF treatment were observed. There was a significant improvement of the regional wall motion and perfusion within the treatment group (P < .0001) and between the treatment and control group (P < .05 and P < .01, respectively). Ejection fraction in the treatment group increased from 0.40 +/- 0.11 to 0.48 +/- 0.13 (P < .01), whereas in the control group, ejection fraction increased from 0.40 +/- 0.13 to 0.43 +/- 0.13 (P = .049). A control angiography of the treatment group after 12.4 +/- 6.6 months showed an in-stent restenosis in 1 patient.

CONCLUSION

In patients with acute myocardial infarction, treatment with G-CSF to mobilize BMCs is feasible and safe and seems to be effective under clinical conditions. The therapeutic effect might be attributed to BMC-associated promotion of myocardial regeneration and neovascularization.

Angiographic, intravascular ultrasound, and fractional flow reserve evaluation of direct stenting vs. conventional stenting using BeStent2 in a multicentre randomized trial

AIMS

Direct stenting (DS) may not be as safe and effective as conventional stenting. The objective was to demonstrate equivalence of post-procedural mean luminal diameter (MLD) by angiography after BeStent2 placement between DS and pre-dilatation (PD) strategy.

METHODS AND RESULTS

Two hundred and two patients with a single de novo lesion (diameter >/=3.0 mm and length </=13 mm) were randomized to DS (n=101) vs. PD. Stent deployment was guided by on-line quantitative coronary angiography (QCA). A second randomization assigned half of the patients to intravascular ultrasound (IVUS) and fractional flow reserve (FFR) assessment. QCA was repeated at 6 months. Baseline characteristics were similar. Crossover to PD was necessary in seven DS patients. Stent deployment was successful in 97% (DS) and 98% (PD). The post-procedural MLD was 2.79+/-0.45 mm (DS) and 2.76+/-0.40 mm (PD). The null-hypothesis of non-equivalence could be rejected (95% one-sided; P=0.0003). The minimum stent area (IVUS) was 7.89+/-1.75 mm(2) (DS) and 8.07+/-2.37 mm(2) (PD; P=0.69), with an FFR of 0.92+/-0.07 and 0.92+/-0.05, respectively (P=0.97). Major adverse cardiac event rates at 6 months were 9% (DS) and 11% (PD; P=0.93). Target lesion re-angioplasty was 6% (DS) and 5% (PD; P=0.77). The in-stent restenosis rate by QCA was 7.4% (DS) and 6.8% (PD; P=0.87).

CONCLUSION

DS with BeStent2 is equivalent to PD. Both strategies resulted in a low angiographic restenosis rate.

Lack of association between Chlamydia Pneumoniae serology and endothelial dysfunction of coronary arteries

BACKGROUND

Recent publications brought up the hypothesis that an infection with Chlamydia Pneumoniae (CP) might be a major cause of coronary artery disease (CAD). Therefore, we investigated whether endothelial dysfunction (ED) as a precursor of atherosclerosis might be detectable in patients with previous infection with CP but without angiographic evidence of CAD.

METHODS

We included 16 patients (6 male / 10 female) of 52 consecutive patients with normal coronary angiography who had typical angina pectoris and pathologic findings in the stress test. Exclusion criteria were: active smoker, elevated cholesterol, hypertension, age > 65 years, diabetes mellitus, treatment with ACE-inhibitors, or known CAD. Blood sample analysis for serum titer against CP (aCP-IgG) was performed after coronary angiography. We looked for endothelial dysfunction analyzing the diameter of the left anterior descending coronary artery (LAD) before and after acetylcholine (ACh) i. c. Quantitative analysis of luminal diameter (LD) was performed in at least two planes during baseline conditions and after ACh for 2 minutes in dosages of 7.2 microg/min and 36 microg/min with an infusion speed of 2 ml/min. Using Doppler guide wire, the coronary flow velocity was measured continuously in the LAD. The coronary flow velocity reserve (CFVR) was measured after 20 microg adenosine i. c.

RESULTS

10 patients had an elevated aCP-IgG (> 1:8). 6 patients with negative titers (aCP-IgG <or= 1:8) served as control (CTRL). Both groups were comparable in age, gender, angina class, results of non-invasive stress-test and the baseline values of LD and flow. In the CP positive group 3 patients (30%) did not show an increase of LD after ACh as evidence of ED. In the CTRL group 4 patients (67 %) had ED. There was no association between aCP-IgG and changes of coronary blood flow after ACh. All patients showed normal CFVR (3.0 +/- 0.27) irrespective of their aCP-IgG values.

CONCLUSION

In patients with typical symptoms of coronary ischemia but without angiographically visible CAD and absence of other factors affecting the endothelial function, a previous infection with CP is not associated with endothelial dysfunction.

Autologous intracoronary mononuclear bone marrow cell transplantation in chronic ischemic cardiomyopathy in humans

BACKGROUND

Recent data suggest that transplantation of autologous bone marrow cells (BMC) may contribute to myocardial repair after acute myocardial infarction. We hypothesized that patients with chronic ischemic cardiomyopathy could also benefit from autologous BMC transplantation in addition to established heart failure therapy.

METHODS AND RESULTS

Five patients with chronic ischemic cardiomyopathy caused by anterior myocardial infarction, 1.3+/-0.5 years ago and open infarct artery, received autologous mononuclear BMC transplantation via balloon catheter in the target vessel at the site of previous occlusion. Patients were followed up at 3 months (left heart catheterisation, 2D-echocardiography, dobutamine stress echocardiography, cardiopulmonary exercise testing) and at 12 months (2D-echocardiography, cardiopulmonary exercise testing). Follow-up examination showed no significant improvement neither in global, regional, and microvascular function, nor in physical performance.

CONCLUSIONS

In this pilot trial intracoronary transplantation of autologous, mononuclear BMC did not lead to any significant improvement in myocardial function and physical performance of patients with chronic ischemic heart disease.

Collaterals and the recovery of left ventricular function after recanalization of a chronic total coronary occlusion

BACKGROUND

A good collateral function in patients with regional myocardial dysfunction may indicate viability with the potential for left ventricular (LV) recovery after revascularization of a chronic total coronary occlusion (CTO).

METHODS

A CTO (duration > 2 weeks) was successfully recanalized in 126 patients. During this procedure, the collateral function was assessed before the first balloon inflation by intracoronary Doppler and pressure wires. Collateral function indexes were calculated. Left ventricular function was assessed by the LV ejection fraction (LVEF) and the wall motion severity index (WMSI [SD/chords]). A repeat angiography was available in 119 patients after 4.9 +/- 1.4 m. An improvement of WMSI > or =1 SD/chord was considered significant.

RESULTS

Left ventricular function was normal in 42%, regional dysfunction with LVEF > or = 0.60 was observed in 16%, and regional dysfunction with LVEF < 0.60 in 42%. The former had a better collateral function than patients with LV dysfunction. In 39% of patients with LV dysfunction, a significant myocardial recovery was observed at follow-up. The collateral function was similar in patients with and without recovery. However, patients with recovery had a lower peripheral resistance as an indicator of a better preserved microvascular integrity.

CONCLUSIONS

Recovery of impaired LV function after revascularization of a CTO is not directly related to the quality of collateral function, as collateral development does not appear to require the presence of viable myocardium. However, a preserved microvascular integrity may be of relevance for myocardial recovery.

Paclitaxel-eluting stents for the treatment of chronic total coronary occlusions: A strategy of extensive lesion coverage with drug-eluting stents

The recanalization of a chronic total coronary occlusion (CTO) is hampered by a high rate of lesion recurrence. The goal of the present study is to assess the effect of paclitaxel-eluting stents in CTOs in a strategy of extensive stent coverage and the optional use of additional bare metal stents (BMSs). In 82 consecutive patients, a CTO (duration > 2 weeks) was successfully recanalized with implantation of one or more Taxus stents. These patients underwent a repeat angiography after 5.0 +/- 1.5 months and were assessed by quantitative angiography. The patients were compared with 82 clinically and lesion-matched patients from a consecutive series of 148 patients with CTOs treated by BMS in the preceding time period. In 21 of the 82 patients, additional lesions in the target artery not directly related to the original occlusion site were treated with BMSs (hybrid approach). The history of diabetes, extent of coronary artery disease, clinical symptoms, and angiographic features were similar in the Taxus and BMS group. Periprocedural adverse events were 3.3% with Taxus and 3.3% with BMS, but 12 months MACE was significantly lower in the group with exclusive use of Taxus (13.3% vs. 56.7%; P < 0.001), mainly due to a lower target lesion revascularization of 10.0% as compared to 53.4% (P < 0.001). There was only one late reocclusion with Taxus (1.7%) as compared to 21.7% with BMS (P < 0.05). However, in the hybrid group, the MACE rate was considerably higher, with 33.3%. Our data of a 80% reduction of target vessel failure as compared to BMS, with a lower risk of late reocclusions without increased acute adverse events, demonstrate the benefit of paclitaxel-eluting stents in CTOs. However, diffuse atherosclerosis in CTOs should be covered completely by the drug-eluting stents.

Prevention of lesion recurrence in chronic total coronary occlusions by paclitaxel-eluting stents

OBJECTIVES

The aim of this research was to assess the efficacy of paclitaxel-eluting stents in chronic total coronary occlusions (CTO).

BACKGROUND

Percutaneous coronary interventions for CTOs are characterized by a high target vessel failure rate.

METHODS

In 48 consecutive patients, paclitaxel-eluting stents (Taxus, Boston Scientific Corp., Natick, Massachusetts) were implanted after successful recanalization of a CTO (duration >2 weeks). Patients underwent an angiography after 6 months and were followed clinically for 12 months. They were compared with 48 lesion- and risk-matched patients with CTOs treated with bare metal stents (BMS). Primary clinical end point was the one-year incidence of major adverse cardiac events (MACE) (death, myocardial infarction, repeat revascularization); secondary end points were the rate of restenosis and re-occlusion.

RESULTS

In-hospital MACE was 4.2% with Taxus, and 2.1% with BMS (p = NS). The one-year MACE rate was 12.5% in the Taxus group, and 47.9% in the BMS group (p < 0.001), which was due to a reduced need for repeat revascularization. The angiographic restenosis rate was 8.3% with Taxus versus 51.1% with BMS (p < 0.001). There was only one late re-occlusion with Taxus (2.1%) as compared with 23.4% with BMS (p < 0.005). The late loss was reduced in the Taxus group by 84% as compared with BMS. All nonocclusive restenoses in the Taxus group were focal and successfully treated by implanting an additional Taxus stent.

CONCLUSIONS

The treatment of CTOs with a paclitaxel-eluting stent drastically reduces MACE and restenosis, and almost eliminates re-occlusion, which is typically frequent with BMS in CTOs. Chronic total coronary occlusion should be a preferred indication for drug-eluting stents.

Transarterial aortic valve replacement with a self expanding stent in pigs

OBJECTIVES

To evaluate the feasibility of percutaneous aortic valve replacement without cardiac arrest in animal experiments.

METHODS

A self expanding nitinol stent, containing pulmonary valves from pigs in its proximal part, was implanted in six pigs (94-118 kg) by means of a 25 French catheter through the left subclavian artery under guidance of fluoroscopy and transoesophageal echocardiography. During stent deployment the original aortic valve was pushed against the aortic wall by the self expanding force of the stent while the new valve was expanded.

RESULTS

It was possible to replace the aortic valve in the beating heart in four pigs (67%) with no complication or relevant drop in blood pressure. The procedure failed in two pigs (33%) due to dysfunction of the catheter device in one case and to problems with correct positioning in the left ventricular outflow tract in the other. After successful stent valve implantation, dopamine was infused in doses of 5 microg/kg/min, 10 microg/kg/min, and 15 microg/kg/min. Cardiac output increased from 4.4 to 8.8 l/min and the mean arterial pressure rose from 79 to 105 mm Hg. The maximum peak to peak pressure gradient across the valve carrying stent reached a maximum of 8 mm Hg under dopamine infusion. All pigs were killed six hours after transvascular aortic valve replacement. The chest was opened, and the left ventricle and the ascending aorta were carefully inspected. There were no signs of malfunction of the implant, of damage of the aortic vessel wall, or of obstruction of the coronary ostia.

CONCLUSIONS

Percutaneous aortic valve replacement with a self expanding nitinol stent in the beating heart is possible. The device was safe under pharmacological stress test. After successful chronic animal experiments, this concept may become a feasible option for treating patients with relevant aortic valve disease but where open heart surgery would be risky.

Recovery of impaired microvascular function in collateral dependent myocardium after recanalisation of a chronic total coronary occlusion

OBJECTIVE

To assess the potential for recovery of impaired microvascular function in collateral dependent myocardium after recanalisation of a chronic total coronary occlusion and the determinants of this recovery.

PATIENTS AND DESIGN

120 patients underwent a successful recanalisation of a chronic total coronary occlusion (duration > 2 weeks) and a follow up angiography after a mean (SD) of 5.0 (1.2) months. The coronary flow velocity reserve (CFVR) and the fractional flow reserve were measured after recanalisation and at follow up. Global and regional left ventricular (LV) function were analysed by quantitative angiography.

RESULTS

Microvascular dysfunction, defined by a CFVR < 2.0 and a fractional flow reserve > or = 0.75, was observed in 55 (46%) patients after recanalisation. Microvascular function improved during follow up in 24 (20%). The CFVR increased during follow up from 2.01 (0.58) to 2.50 (0.79) (p < 0.001), due to a decrease in basal average peak velocity from 30.7 (14.9) cm/s to 25.5 (13.3) cm/s (p = 0.001). Improved microvascular function was associated with an improved regional LV function, shown by a correlation between increased wall motion severity index and increased CFVR (r = 0.38, p = 0.003). The major determinant of microvascular dysfunction at baseline was the presence of diabetes mellitus (odds ratio 4.3, 95% confidence interval 1.8 to 10.2), which remained so at follow up (odds ratio 4.1, 95% confidence interval 1.3 to 13.4). Improvement of LV function was not impaired by the presence of microvascular dysfunction after recanalisation.

CONCLUSIONS

The frequently observed microvascular dysfunction after recanalisation of a chronic total coronary occlusion is a transient phenomenon in most patients and is influenced by the presence of diabetes mellitus. It does not impede the recovery of LV function. Improved regional LV function is associated with improved microvascular function.