The BioMimics 3D Helical Centreline Nitinol Stent in Chronic Limb Threatening Ischaemia and Complex Lesions: Three Year Outcomes of the MIMICS-3D Registry

OBJECTIVE

There is a need for improved outcomes in the endovascular treatment of patients suffering from chronic limb threatening ischaemia (CLTI), highly calcified lesions, and chronic total occlusions (CTOs). The helical centreline self expanding BioMimics 3D stent might be particularly useful in these high risk subsets, combining flexibility and fracture resistance with radial strength. Herein, the performance of the BioMimics 3D stent was assessed in these high risk subsets.

METHODS

MIMICS-3D is a prospective, multicentre, European real world registry. This was a post hoc analysis, comparing patients with CLTI vs. intermittent claudication (IC), lesions with bilateral calcification vs. those without (peripheral arterial calcium scoring system [PACSS] 3,4 vs. PACSS 0 - 2), and CTO vs. no CTO. Propensity score matching was performed to reduce the impact of baseline variables. The 36 month endpoints were clinically driven target lesion revascularisation (CD-TLR), death, major target limb amputation, and stent patency.

RESULTS

A total of 507 patients were enrolled. At 36 months, patients with CLTI had lower freedom from major amputation than patients with IC (92.6% vs. 100%, p < .001). In terms of primary patency, patients with CTO had lower patency rates than those without (63.9% vs. 77.8%, p = .003), but the difference reduced after propensity score matching (70.5% vs. 76.8%, p = .43). Primary patency was not impaired for patients with PACSS 3,4 or patients with CLTI. Freedom from CD-TLR was not significantly different among the groups and was 73.8% for CLTI vs. 78.9% for IC (p = .15), 77.6% for PACSS 3,4 vs. 78.7% for PACSS 0 - 2 (p = .55), and 75.6% for CTO vs. 81.0% for no CTO (p = .11).

CONCLUSIONS

The outcome of the MIMICS-3D registry suggests that the BioMimics 3D stent is effective in the endovascular treatment of complex femoropopliteal lesions and in CLTI. Future randomised controlled trials should confirm its non-inferiority or superiority compared with existing alternatives.

Impact of Access Site on Periprocedural Bleeding and Cerebral and Coronary Events in High-Bleeding-Risk Percutaneous Coronary Intervention: Findings from the RIVA-PCI Trial

INTRODUCTION

The preference for using transradial access (TRA) over transfemoral access (TFA) in patients requiring percutaneous coronary intervention (PCI) is based on evidence suggesting that TRA is associated with less bleeding and fewer vascular complications, shorter hospital stays, improved quality of life, and a potential beneficial effect on mortality. We have limited study data comparing the two access routes in a patient population with atrial fibrillation (AF) undergoing PCI, who have a particular increased risk of bleeding, while AF itself is associated with an increased risk of thromboembolism.

METHODS

Using data from the RIVA-PCI registry, which includes patients with AF undergoing PCI, we analyzed a high-bleeding-risk (HBR) cohort. These patients were predominantly on oral anticoagulants (OAC) for AF, and the PCI was performed via radial or femoral access. Endpoints examined were in-hospital bleeding (BARC 2-5), cerebral events (TIA, hemorrhagic or ischemic stroke) and coronary events (stent thrombosis and myocardial infarction).

RESULTS

Out of 1636 patients, 854 (52.2%) underwent TFA, while 782 (47.8%) underwent the procedure via TRA, including nine patients with brachial artery puncture. The mean age was 75.5 years. Groups were similar in terms of age, sex distribution, AF type, cardiovascular history, risk factors, and comorbidities, except for a higher incidence of previous bypass surgeries, heart failure, hyperlipidemia, and chronic kidney disease (CKD) with a glomerular filtration rate (GFR) < 60 ml/min in the TFA group. No clinically relevant differences in antithrombotic therapy and combinations were present at the time of PCI. However, upon discharge, transradial PCI patients had a higher rate of triple therapy, while dual therapy was preferred after transfemoral procedures. Radial access was more frequently chosen for non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP) cases (NSTEMI 26.6% vs. 17.0%, p < 0.0001; UAP 21.5% vs. 14.5%, p < 0.001), while femoral access was more common for elective PCI (60.3% vs. 44.1%, p < 0.0001). No differences were observed for ST-segment elevation myocardial infarction (STEMI). Both groups had similar rates of cerebral events (TFA 0.2% vs. TRA 0.3%, p = 0.93), but the TFA group had a higher incidence of bleeding (BARC 2-5) (4.2% vs. 1.5%, p < 0.01), mainly driven by BARC 3 bleeding (1.5% vs. 0.4%, p < 0.05). No significant differences were found for stent thrombosis and myocardial infarction (TFA 0.2% vs. TRA 0.3%, p = 0.93; TFA 0.4% vs. TRA 0.1%, p = 0.36).

CONCLUSIONS

In HBR patients with AF undergoing PCI for acute or chronic coronary syndrome, the use of TRA might be associated with a decrease in in-hospital bleeding, while not increasing the risk of embolic or ischemic events compared to femoral access. Further studies are required to confirm these preliminary findings.

BioMimics 3D Stent in Femoropopliteal Lesions: 3-Year Outcomes with Propensity Matching for Drug-Coated Balloons

Background: Through its helical centreline geometry, the BioMimics 3D vascular stent system is designed for the mobile femoropopliteal region, aiming to improve long-term patency and the risk of stent fractures. Methods: MIMICS 3D is a prospective, European, multi-centre, observational registry to evaluate the BioMimics 3D stent in a real-world population through 3 years. A propensity-matched comparison was performed to investigate the effect of the additional use of drug-coated balloons (DCB). Results: The MIMICS 3D registry enrolled 507 patients (518 lesion, length 125.9 ± 91.0 mm). At 3 years, the overall survival was 85.2%, freedom from major amputation 98.5%, freedom from clinically driven target lesion revascularisation 78.0%, and primary patency 70.2%. The propensity-matched cohort included 195 patients in each cohort. At 3-year follow-up, there was no statistically significant difference in clinical outcomes, such as overall survival (87.9% in the DCB vs. 85.1% in the no DCB group), freedom from major amputation (99.4% vs. 97.2%), clinically driven TLR (76.4% vs. 80.3%), and primary patency (68.5% vs. 74.4%). Conclusion: The MIMICS 3D registry showed good 3-year outcomes of the BioMimics 3D stent in femoropopliteal lesions, demonstrating the safety and performance of this device under real-world conditions, whether used alone or in combination with a DCB.

Current status of antithrombotic therapy and in-hospital outcomes in patients with atrial fibrillation undergoing percutaneous coronary intervention in Germany

BACKGROUND

Little is known about current patterns of antithrombotic therapy in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) in clinical practice in Germany.

METHODS

The RIVA-PCI is a prospective, non-interventional, multicenter study with follow-up until hospital discharge including consecutive patients with AF undergoing PCI.

RESULTS

Between January 2018 and March 2020, 1636 patients (elective in 52.6%, non-ST elevation acute coronary syndrome [NSTE-ACS] in 39.3%, ST-elevation myocardial infarction in 8.2%) from 51 German hospitals were enrolled in the study. After PCI a dual antithrombotic therapy (DAT) consisting of OAC and a P2Y12 inhibitor was given to 66.0%, triple antithrombotic therapy (TAT) to 26.0%, dual antiplatelet therapy to 5.5%, and a mono-therapy to 2.5% of the patients. Non-vitamin K antagonist oral anticoagulants (NOACs) were given to 82.4% and vitamin K antagonists to 11.5% of the patients. In-hospital events included death in 12 cases (0.7%), myocardial infarction, stent thrombosis, and ischemic stroke in four (0.2%) patients each, while 2.8% of patients had bleeding complications. The recommended durations for DAT or TAT at discharge were 1 month (1.5%), 3 months (2.1%), 6 months (43.1%), and 12 months (45.6%), with a 6-month course of DAT (47.7%) most often recommended after elective PCI and a 12-month course of DAT (40.1%) after ACS.

CONCLUSION

The preferred therapy after PCI in patients with AF is DAT with a NOAC and clopidogrel. In-hospital ischemic and bleeding events were rare. The recommended durations for combination therapy vary considerably.

Rivaroxaban in Patients With Atrial Fibrillation Who Underwent Percutaneous Coronary Intervention in Clinical Practice

Little is known about the efficacy and safety of rivaroxaban in patients with atrial fibrillation (AF) who underwent percutaneous coronary intervention (PCI) in clinical practice. We therefore conducted a prospective observational study to determine the rate of ischemic, embolic, and bleeding events in patients with AF and PCI treated with rivaroxaban in a real-world experience. The RIVA-PCI ("rivaroxaban in patients with AF who underwent PCI") (clinicaltrials.gov NCT03315650) is a prospective, noninterventional, multicenter study with a follow-up until 14 months, including patients with AF who underwent PCI discharged with rivaroxaban. Between January 2018 and March 2020, 700 patients with PCI treated with rivaroxaban (elective in 50.1%, non-ST-elevation acute coronary syndrome 43.0%, ST-elevation myocardial infarction in 6.9%) were enrolled at 51 German hospitals. After PCI, a dual antithrombotic therapy consisting of rivaroxaban and a P2Y12 inhibitor was administered in 70.7% and triple antithrombotic therapy in 27.9%, respectively. Follow-up information could be obtained in 695 patients (99.3%). Rivaroxaban has been stopped prematurely in 21.6% of patients. Clinical events under rivaroxaban during the 14-month follow-up compared with those observed in the PIONEER-AF PCI trial included cardiovascular death (2.0% % vs 2.0%), myocardial infarction (0.9% vs 3.0%), stent thrombosis (0.2% vs 0.8%), stroke (1.3% vs 1.3%), International Society on Thrombosis and Haemostasis major (4.2% vs 3.9%), and International Society on Thrombosis and Haemostasis nonmajor clinically relevant bleeding (15.3% vs 12.9%). Therefore, in this real-world experience, rivaroxaban in patients with AF who underwent PCI is associated with ischemic and bleeding event rates comparable with those observed in the randomized PIONEER-AF PCI trial.

Prospective Study of Serration Angioplasty in the Infrapopliteal Arteries Using the Serranator Device: PRELUDE BTK Study

PURPOSE

The purpose was to evaluate the safety and efficacy of the Serranator percutaneous transluminal angioplasty serration balloon catheter in patients with infrapopliteal peripheral artery disease.

MATERIALS AND METHODS

A prospective, multicenter, single-arm feasibility study in 46 patients with claudication or chronic limb-threatening ischemia, Rutherford Clinical Category (RCC) 3 to 5, that required treatment of the infrapopliteal arteries above the tibiotalar joint. The primary efficacy outcome was device success-successful insertion, balloon inflation and deflation, and removal of the device(s) with a final diameter stenosis of <50%. The primary safety endpoint was a composite of major adverse limb events (MALE) and perioperative death (POD) through 30 day postprocedure. Other outcomes were change in RCC and ankle-brachial index, wound healing, and clinically-driven target lesion revascularization (CD-TLR). A subset of 9 patients were further evaluated by optical coherence tomography (OCT) or intravascular ultrasound (IVUS) for the presence of serrations in treated lesions. Patient follow-up occurred at 30 days and 6 months.

RESULTS

Forty-six patients received treatment with the Serranator device and 55 lesions were treated. Fifty-three lesions were deemed analyzable by the core lab with data and reported hereafter. Device success was 91.7% and freedom from MALE + POD through 30 days was 95.7%. Pretreatment stenosis of 82% was reduced to 21.8% and only 1 lesion (1.9%) required a bailout stent for a grade D dissection. The average maximum balloon inflation pressure was 6 atmospheres. Serrations were present in all treated lesions (n=10) in 9 patients imaged with OCT/IVUS as reviewed by the core laboratory. The RCC score improved by 1 or more level in 70% of patients at 6 months with 42% having a score of 0. The 6 month freedom from CD-TLR was 97.7%.

CONCLUSION

Serranator treatment of infrapopliteal lesions showed excellent lumen gain with minimal evidence of arterial injury and low 6 month CD-TLR. Imaging by IVUS and OCT showed serrations without significant dissection, supporting the device's proposed mechanism of action.

Twelve-Month Results of Tack-Optimized Balloon Angioplasty Using the Tack Endovascular System in Below-the-Knee Arteries (TOBA II BTK)

Purpose: To report the 12-month safety and efficacy outcomes of the investigational device exemption trial evaluating an implantable below-the-knee (BTK) dissection repair device. Materials and Methods: The prospective, multicenter, single-arm Tack-Optimized Balloon Angioplasty (TOBA) II BTK study (ClinicalTrials.gov identifier NCT02942966) evaluated the Tack Endovascular System in the BTK arteries vs objective performance goals derived from a systematic review of BTK angioplasty literature. Patients presenting with Rutherford category 3-5 ischemia were eligible and were enrolled during the procedure if angioplasty resulted in dissection(s) of the BTK arteries. Between February 2017 and December 2018, the study enrolled 233 patients (mean age 74.4±10.0 years; 157 men). Most lesions (93.8%) were de novo; almost half (118/248, 47.6%) were total occlusions. Mean target lesion length was 80±49 mm. Moderate to severe calcium was present in 89 (35.8%) lesions. The 30-day primary safety endpoint was a composite of major adverse limb events (MALE) and all-cause perioperative death (POD). The primary efficacy endpoint was a composite of MALE at 6 months and 30-day POD. These safety and efficacy endpoints were assessed at 12 months as observational endpoints along with amputation-free survival (AFS), freedom from clinically-driven target lesion revascularization (CD-TLR), vessel patency, and changes from baseline in clinical and quality of life measures. Results: All patients had post-PTA dissection and received at least 1 Tack implant (range 1 to 16). The angiographic core laboratory noted successful resolution of 100% of the 341 treated dissections. At 12 months, 93.4% (170/182) of patients remained free of the composite endpoint of MALE + POD. Tacked segment patency was 81.3% and limb salvage was 96.8% at 12 months; freedom from CD-TLR and AFS were 83.1% and 89.3%, respectively. Sustained Rutherford category improvement was reported in 82.4% of evaluated patients, with 62.4% improving ≥3 categories (p<0.001). Ninety of 124 index wounds (72.5%) healed or improved. Conclusion: The Tack Endovascular System is safe and effective in the treatment of post-angioplasty BTK dissections. Twelve-month outcome data from the TOBA II BTK study demonstrate high rates of patency, limb salvage, and wound healing.

Renal denervation for hypertension refractory to renal artery stenting

PURPOSE

To investigate the effect of renal denervation (RDN) on blood pressure and renal function in refractory hypertension after renal artery recanalization and optimal medical therapy.

METHODS

Ten patients (6 women; mean age 70.0±5.1 years) with an office systolic blood pressure >160 mmHg despite taking ≥3 antihypertensive drugs and uni- or bilateral renal artery stenting were treated with RDN. Radiofrequency (RF) energy was delivered to the native segment of the artery keeping a 5-mm safe distance from the stented segments. Standardized office (OBP) and ambulatory (ABP) blood pressure measurements, medication, and renal assessment, including renal duplex ultrasound and renal function, were determined at baseline and on follow-up to 12 months.

RESULTS

OBP (systolic/diastolic) at baseline was 190.0±20.4 / 84.2±10.1 mmHg. It decreased to 171.1±28.7* / 82.2±8.7, 165.5±28.4(†) / 76.1±7.4, and 158.3±14.2(†) / 75.5±9.5(†) mmHg (*p<0.001; (†)p<0.01) at 3, 6, and 12 months after RDN, respectively. Average ABP (systolic/diastolic) after 6 and 12 months decreased by -7.6(‡) / -3.1 and -11.3(‡) / -5.1(‡) mmHg ((‡)p<0.05). There was no renal artery (re)stenosis, dissection, or aneurysm within 12 months. Creatinine, cystatin C, and glomerular filtration rate remained unchanged. Urine albumin excretion decreased in 4/10 patients. Renal resistive indices improved in native, but not in stented renal arteries within the follow-up period.

CONCLUSION

This proof-of-concept study demonstrates that RF-based RDN can be safely and effectively delivered in patients with resistant hypertension and previous renal artery stenting.

Endovascular brachytherapy using liquid Beta-emitting rhenium-188 for the treatment of long-segment femoropopliteal in-stent stenosis

PURPOSE

To evaluate the efficacy and safety of endovascular brachytherapy with liquid beta-emitting rhenium-188 (Re-188) in patients with long-segment in-stent stenosis in the femoropopliteal segment.

METHODS

From July 2009 to April 2011, 90 consecutive patients (59 men; mean age 68.3±10.3 years, range 43-86) with symptomatic in-stent stenosis/occlusion (24.6-cm mean lesion length) of the femoropopliteal segment underwent angioplasty and subsequent endovascular brachytherapy. The liquid beta-emitting Re-188 was applied to the target lesion within an angioplasty balloon using a dose of 13 Gy at a depth of 2 mm into the vessel wall. Clinical and angiographic follow-up data were collected up to 2 years. The main study endpoints were the 6- and 12-month primary patency rates defined as <50% in-stent stenosis as detected by duplex ultrasound. Clinical endpoints were the cumulative rates of death, amputation, and bypass surgery, as well as improvement in the Rutherford category and the ankle-brachial index. Results were correlated with patient and lesion characteristics.

RESULTS

Primary technical success was achieved in all patients, with 1 early stent thrombosis, but no other complications related to the irradiation. Eighty-eight patients reached the 6-month and 82 the 12-month examinations; the primary patency was 95.2% and 79.8%, respectively. In-stent stenosis occurred in 9 patients, while 10 patients had reocclusion of the treated segment. During follow-up, there were 2 late acute thrombotic occlusions, both after discontinuation of clopidogrel. The clinical status improved in 67.0% and 62.2% of the patients after 6 and 12 months, respectively. No patient, lesion, or procedure variables were predictive of restenosis after EVBT.

CONCLUSION

EVBT with liquid beta-emitting Re-188 was safe and effective in preventing restenosis in long-segment femoropopliteal ISS.

Tako-Tsubo Cardiomyopathy

Tako-Tsubo cardiomyopathy (TTC) is described as left ventricular (LV) dysfunction with the phenomenon of "apical ballooning", rapidly resolving, without coronary artery stenoses.

METHODS

Fifteen patients with TTC and transthoracic echocardiography (TTE) at their admission, were reviewed (2001 to 2006). Follow-up (F/U) TTE was performed in varying intervals. To compare diameters of posterior wall (PW), interventricular septum (IVS), left atrium (LA), LV in end-diastole (LVED) and LV in end-systole (LVES) and valve insufficiencies, patients with comparable F/U are selected.

RESULTS

Fourteen patients were female (mean age 69.6 years). Angiography demonstrated LV systolic dysfunction with mean ejection fraction (EF) of 31.3%. In the acute-phase (day 0 to day 3), TTE showed a mean EF of 35.7%, not significantly different from EF obtained in angiography. Short-term F/U was performed in 9 patients after median time-interval of 20 days with an increase to a mean EF of 58.8%. F/U in 2006 has been performed in 10 patients (median time-interval 18.7 months) and showed normal EF. No significant difference in diameters of LA, LVED and LVES could be obtained comparing baseline and long-term data (p=0.493, p=0.790 and p=0.275). PW and IVS were significantly thicker at baseline compared to TTE > or = day 62 of F/U (p=0.003 and p=0.026). At baseline mitral valve insufficiency (MI) was mild in 50.0% and moderate in 12.5%, mild and moderate tricuspid valve insufficiency (TI) was recognized in 50% (25% respectively). MI and TI were regredient in F/U. In three patients an intraventricular systolic flow acceleration could be detected in the acute phase.

CONCLUSIONS

Characteristics of TTC, besides transient LV apical ballooning are also a significant change in LV wall thickness and reversible valve insufficiencies.

Successful trapping of an organized thrombus in a coronary artery aneurysm in myocardial infarction: case report and literature review

A 44-year-old female presented with acute inferior myocardial infarction. Emergency coronary angiography showed an aneurysm of the proximal right coronary artery and an occlusion of the vessel downstream due to a huge organized thrombus. Mechanical fragmentation, glycoprotein IIb/IIIa antagonist, and intracoronary thrombolysis were all tested without success. Finally, the aneurysm was covered with a standard bare metal stent in order to trap the thrombus between the stent and the vessel wall and at least partially in the aneurysm. The strategy was successful, and after 1 week, the blood flow in the right coronary artery was normal; however, the aneurysm remained. After 6 months, there was significant in-stent restenosis of the proximal and mid segments of the right coronary artery but no evidence of the aneurysm. The restenosis was treated with two drug-eluting stents, leading to an excellent result after a further 6 months. The patient was free of symptoms and the left ventricular ejection fraction was within the normal range.

Stenting of unprotected left main stem stenosis: Results from a German single-centre registry

OBJECTIVE

To elucidate the influence of drug-eluting stents (DESs) on interventional therapy of de novo unprotected left main stem (LMS) lesions in a hospital with on-site cardiac surgery.

METHODS AND RESULTS

A retrospective study of all patients with unprotected LMS angioplasty from 1999 to 2005 was conducted with regard to clinical and procedural data, and follow-up data. Fifty-four patients with unprotected LMS stenosis were treated inter-ventionally. Of these patients, 16 were treated with DESs. Seven patients presented with cardiogenic shock. During their hospital stay, four patients died (all treated with bare metal stents [BMSs], three initially presenting with cardiogenic shock). Follow-up data for 53 patients (98%) were obtained. Median follow-up time was 24 months (25th percentile, 12 months; 75th percentile, 35 months). Survival after nine months was 87% (81% from the BMS-treated group, and 100% from the DES-treated group). Control angiography had been performed in 36 patients (67%). Patients with unprotected LMS with an angiographic follow-up had a higher nine-month survival rate than patients without (36 of 36 patients [100%] versus 10 of 17 patients [59%], respectively; P<0.0001). Target lesion revascularization rate was 19% in both the BMS and the DES groups. Methods of revascularization did not vary significantly between the groups.

CONCLUSIONS

In the present study of selected patients with LMS stenosis, the use of DESs showed a low mortality rate but did not have a clear effect on target lesion revascularization rate compared with BMSs. A close follow-up appears to be mandatory to achieve acceptable results.

Aneurysm of the left main stem leading to anterior wall infarction

We report a case of a woman with a spontaneous dissection of the left main stem leading to a large aneurysm compressing the left coronary artery. The lesion was initially treated with a conventional multicellular stent. However, persistence of the aneurysm required that two polytetrafluoroethylene-covered stents be implanted. Follow-up angiographic and clinical results were excellent.

Percutaneous endocardial injection of erythropoietin: Assessment of cardioprotection by electromechanical mapping

BACKGROUND

Apart from its well-known stimulation of erythropoiesis, erythropoietin (EPO) exhibits angiogenic and anti-apoptotic effects. These cellular protective effects have also been described in experimental acute myocardial infarction models. We investigated the effects of EPO in a porcine model of chronic progressive myocardial ischaemia.

METHODS

At weeks 2 and 6 after implantation of a circumflex ameroid constrictor, endocardial electromechanical NOGA system (Biosense Webster, Inc., California, USA) mapping of the left ventricle, coronary and ventricular angiography, as well as echocardiography were performed. Two weeks after ameroid placement, 13 pigs were randomized with 7 pigs receiving 10.000 U EPO and 6 pigs receiving placebo into the ischaemic region using a NOGA guided percutaneous transendocardial injection catheter, MYOSTAR. After 6 weeks, histology (Masson's Trichrome) was analyzed.

RESULTS

Endocardial electromechanical mapping showed an increase of mean unipolar voltage (UV) amplitude in the ischaemic myocardial segments in the EPO-treated animals (8.5 mV pre and 10.6 mV post treatment) and a significantly reduced ischaemic surface area compared to the control group (19% vs. 41%) suggesting a decline in ischaemic injury. Echocardiography revealed 2,2 hypokinetic segments of the lateral wall in the EPO group vs. 3,3 in the control groups. The mean ejection fraction was 64% in the EPO group and 55% in the placebo group. Quantitative histological analysis of the ischaemic regions revealed a reduction of myocardial fibrosis (8% vs. 28%) in the EPO group.

CONCLUSION

Endocardial EPO injection may induce cardioprotective effects in hibernating myocardium and may attenuate the progression of ischaemic tissue damage.

Tissue velocity imaging during dobutamine stimulation for assessment of myocardial viability: Segmental analysis in patients after myocardial infarction

BACKGROUND

Dobutamine stress echocardiography (DSE) is an established method for the detection of viable myocardium, but evaluation of this method is subjective. Tissue velocity Imaging (TVI) allows quantitative analysis of regional myocardial wall motion by assessment of systolic myocardial velocities. The aim of this study was to evaluate the diagnostic value of DSE and TVI for detection of viable myocardium.

METHODS

In 56 patients (58+/-12 years) with previous myocardial infarction (130+/-42 days, mean ejection fraction 42+/-15%) low-dose DSE was combined with analysis of peak systolic myocardial velocities (Vpeak) by TVI for assessment of myocardial viability. As reference served a follow-up echocardiography after successful revascularization (mean 91+/-3 days).

RESULTS

Of a total of 896 segments 200 showed abnormal wall motion (31 mildly hypokinetic, 50 severely hypokinetic, 115 akinetic, 4 dyskinetic). In 125 of these 200 segments regional improvement of regional wall motion was observed (62.5% viable). An increase of Vpeak>1 cm/s during dobutamine stimulation allowed the identification of viable myocardium with a sensitivity of 82% and a specificity 82% (DSE: 77% and 80%). By receiver operating characteristic (ROC) curve analysis, a cut-off value of 1.0 cm/s was the best parameter to differ viable from nonviable myocardium (area under the curve 0.85; p<0.01; 95% CI 0.79 to 0.90). Improvement of global ejection fraction after revascularization (47+/-13%, p=0.11) corresponded with three TVI viable segments with a sensitivity of 92% and a specificity of 89% (p=0.012).

CONCLUSIONS

TVI allows the identification of viable myocardium during dobutamine stimulation and enables a quantitative interpretation of DSE.

Transient left ventricular apical ballooning in a community hospital in Germany

INTRODUCTION

Tako-tsubo cardiomyopathy represents an intermittent left ventricular dysfunction with a ballooning of the left ventricular apical myocardium without significant coronary artery disease. Precise epidemiological data are not yet available.

METHODS AND RESULTS

We retrospectively reviewed 16,989 cases with diagnostic angiographies in our catheter laboratory from January 2001 until December 2004 for intermittent left ventricular apical ballooning. Thirty-two (0.2%) patients were included (50% of all cases presented in 2004, 50% of all cases during the summer months). Twenty-nine (91%) were female, median age was 67.5 years. Fourteen patients (44%) were known to have chronic obstructive pulmonary disease or asthma. Thirteen patients (41%) reported an acute stressful event prior to onset of symptoms. Twenty-five (78%) of the patients presented with clinical signs of an acute coronary syndrome with positive troponin T in 20 (63%) patients. Median left ventricular ejection fraction was 42.5%. Follow-up data of 30 patients (94%) could be obtained; median follow-up time is 6 months. Two patients died during follow-up (malignancy; unknown cause). Echocardiography was performed in 26 (81%) patients; median ejection fraction was 70%.

CONCLUSION

Tako-tsubo-like cardiomyopathy might be considered a differential diagnosis for acute coronary syndrome especially in elderly women. Chronic pulmonary diseases may be associated with a higher risk. The reason for the increasing number of cases during the last year is not clear; however, the tendency for early angiography in acute coronary syndrome may have contributed. The reason for the accumulation of cases during the summer months is also not yet understood.

Use of the novel magnetic navigation system Niobe in percutaneous coronary interventions; the Hamburg experience

INTRODUCTION

In interventional cardiology an increasing demand to treat complex coronary lesions (i.e. distal lesions, tortuous vessels, chronic occlusions) has developed within the last years. New devices to fulfill this demand are therefore needed.

METHODS AND RESULTS

The magnetic navigation system (Niobe System; Stereotaxis Inc.) represents a novel system which allows 3-dimensional control of the guide wire tip using magnetic fields. Two computer controlled permanent magnets on each side of the patient create a uniform magnetic field which can freely be directed. A small magnet at the guide wire tip will align according to the vector of the magnetic field. Advancing and retracting of the wire is to be done manually. The remaining steps of angioplasty (i.e. balloon angioplasty and stent implantation) are performed conventionally, after magnetically guided crossing of the target lesion.The study was performed to proof the feasibility of the technique in the treatment of coronary lesions. Seventy seven patients with 82 coronary lesions underwent magnetic guided coronary interventions. Sixty three lesions (77%) could be crossed successfully using magnetic guidance, 13 more by switching to conventional guide wires. Successful angioplasty (with or without stent implantation) was achieved in 74 lesions (90%). Mean fluoroscopy time was 13,9+/-8 min.

CONCLUSIONS

The use of magnetic guidance in coronary interventions is a promising tool to treat complex coronary lesions. With more experience and improved devices (i.e. coated wires, steerable microcatheters) the safety and efficacy of the procedures should be improved.

Different cardiorespiratory responses to hemorrhage and hyperoxia in normotensive (WKY) and spontaneously hypertensive (SHR) rats

OBJECTIVE

To compare the cardiorespiratory responses underlying the beneficial effects of hyperoxia during blood loss between normotensive (WKY) and hypertensive (SHR) rats.

METHODS

Experiments were carried out in anesthetized animals with both carotid bifurcations either innervated or denervated. The effects of breathing 60% O2 in N2 were studied either in combination with non-hypotensive hemorrhage or during hemorrhagic hypotension.

RESULTS

In normoxia arterial pressure fell more in SHR than in WKY for a given blood loss. During hyperoxia, nerve-intact rats showed initial suppression of ventilation, but bifurcation-denervated rats a powerful enhancement. In all groups, hyperoxia increased the overall tone of venous capacitance vessels.

CONCLUSIONS

The greater blood loss in SHR than in WKY when bleeding down to a given arterial pressure results from a stronger constriction of venous capacitance vessels. Hyperoxia improves the ability of the cardiorespiratory system to resist the effects of hemorrhage by increasing the overall venous tone, thus supporting cardiac filling, and in some cases also by increasing alveolar ventilation, probably secondary to improved cerebral oxygenation. The beneficial effects of hyperoxia were: (i) not prevented by carotid denervation, and thus were presumably direct tissue effects of oxygen, (ii) strikingly weaker in SHR than in normotensive (WKY) rats.

Initial experience with remote catheter ablation using a novel magnetic navigation system: magnetic remote catheter ablation

BACKGROUND

Catheters are typically stiff and incorporate a pull-wire mechanism to allow tip deflection. While standing at the patient's side, the operator manually navigates the catheter in the heart using fluoroscopic guidance.

METHODS AND RESULTS

A total of 42 patients (32 female; mean age, 55+/-15 years) underwent ablation of common-type (slow/fast) or uncommon-type (slow/slow) atrioventricular nodal reentrant tachycardia (AVNRT) with the use of the magnetic navigation system Niobe (Stereotaxis, Inc). It consists of 2 computer-controlled permanent magnets located on opposite sides of the patient, which create a steerable external magnetic field (0.08 T). A small magnet embedded in the catheter tip causes the catheter to align and to be steered by the external magnetic field. A motor drive advances or retracts the catheter, enabling complete remote navigation. Radiofrequency current was applied with the use of a remote-controlled 4-mm, solid-tip, magnetic navigation-enabled catheter (55 degrees C, maximum 40 W, 60 seconds) in all patients. The investigators, who were situated in the control room, performed the ablation using a mean of 7.2+/-4.7 radiofrequency current applications (mean fluoroscopy time, 8.9+/-6.2 minutes; procedure duration, 145+/-43 minutes). Slow pathway ablation was achieved in 15 patients, whereas slow pathway modulation was the end point in the remaining patients. There were no complications.

CONCLUSIONS

The Niobe magnetic navigation system is a new platform technology allowing remote-controlled navigation of an ablation catheter. In conjunction with a motor drive unit, this system was used successfully to perform completely remote-controlled mapping and ablation in patients with AVNRT.

Modulation of the slow pathway in the presence of a persistent left superior caval vein using the novel magnetic navigation system Niobe

AIMS

This is the first report of a young female with typical AVNRT in the presence of a persistent left superior caval vein that underwent catheter ablation using the novel magnetic navigation system (MNS) Niobe (Stereotaxis Inc.).

METHODS

The MNS consists of two outer permanent magnets (about 0.1 T) that align a third small magnet integrated in the tip of a mapping and ablation catheter along its magnetic field lines. By changing the orientation of the outer magnets, the orientation of the magnetic field lines also change, thereby allowing navigation of the ablation catheter. In combination with an automated advancer system, this novel technique allows for the first time complete remote catheter ablation.

RESULTS

Successful slow pathway modulation was performed using a total of seven radiofrequency current applications via the magnetic ablation catheter. No complication occurred.

CONCLUSIONS

The novel magnetic navigation system proved to be a safe and feasible tool for remote catheter ablation of common type AVNRT in the presence of a persistent left superior caval vein.

Electromechanical mapping for determination of myocardial contractility and viability. A comparison with echocardiography, myocardial single-photon emission computed tomography, and positron emission tomography

OBJECTIVE

The purpose of this study was to validate electromechanical viability parameters with combined myocardial perfusion and metabolic imaging and echocardiography.

BACKGROUND

The NOGA System is a catheter-based, non-fluoroscopic, three-dimensional endocardial mapping system. This unique technique allows accurate simultaneous assessment of both local electrical activity and regional contractility.

METHODS

The results of NOGA, myocardial single-photon emission computed tomography (SPECT), positron emission tomography, and echocardiography in 51 patients with coronary artery disease and a pathologic SPECT study were transcribed in a nine-segment bull's-eye projection and compared. The local shortening of normally contracting segments, as shown by echocardiography, was 9.2 +/- 5.1%, which decreased to 6.6 +/- 5.0% and 4.1 +/- 5.2% in hypokinetic and akinetic segments. The highest unipolar voltage (11.2 +/- 5.0 mV) and local shortening (8.2 +/- 5.0%) characterized normally perfused segments. Fixed perfusion defects with normal or limited 18-fluoro-2-deoxy-D-glucose uptake indicating viability had a significantly higher unipolar voltage than did scar tissue (7.25 +/- 2.7 vs. 5.0 +/- 3.1 mV, p = 0.029).

CONCLUSION

Electromechanical parameters sufficiently defined the viability state of the myocardium and showed good concordance with the findings by nuclear perfusion and metabolism imaging and echocardiography. The NOGA technique provides all the relevant information immediately after coronary angiography and enables the physician to proceed with therapy in the same setting.

[Electromechanical mapping as a platform for myocardial laser therapy]

Percutaneous myocardial laser therapy is a new strategy for myocardial revascularization in patients with end-stage coronary artery disease. The laser impulse which is applied via a catheter creates small channels into ischemic myocardium from the endocardial surface. Different mechanisms such as angiogenesis, improved blood flow via open channels or neural stunning are discussed as the underlying mechanism. Precise identification and maneuvering of the laser catheter to the target zone is of crucial importance. By using a novel catheter-based, non-fluoroscopic, three-dimensional endocardial mapping system (NOGA, Biosense-Webster Co.) accurate simultaneous assessment of both local electrical activity and regional contractility can be obtained. The analysis of uni- or bipolar voltage and linear local shortening allows an exact differentiation of scar tissue from viable myocardium. In addition, due to the high spatial resolution of the NOGA system the application of laser channels at the same site can be avoided, which increases the safety of the procedure. To assess the efficacy of the NOGA based myocardial lasing procedure a multicenter randomized study (Euro-direct) is presently underway.