Challenging Case of Transcatheter Mitral Valve-in-Valve-in-Valve Replacement.

BACKGROUND A 39-year-old man with a complex valvular history of recurrent methicillin-resistant Staphylococcus aureus endocarditis with 2 surgical mitral valve replacements (in 2016 and 2017) followed by transcatheter mitral valve replacement (in 2019) presented with orthopnea, paroxysmal nocturnal dyspnea, chest pain, cough, and progressively worsening dyspnea on exertion. CASE REPORT Extensive workup was performed, including transesophageal echocardiogram, which revealed a malfunctioning, severely stenotic bioprosthetic valve. Left and right heart catheterization revealed mild non-obstructive coronary artery disease and severe pulmonary hypertension. Given the patient's complex medical history, he was deemed to be at an elevated risk for repeat sternotomy and repeat valve replacement surgery. Therefore, he underwent a percutaneous transcatheter mitral valve replacement with a 26-mm SAPIEN 3 Edwards valve placed within the previous 29-mm SAPIEN valve. Post-procedural imaging revealed a well-placed valve with an improved mitral valve gradient. CONCLUSIONS This is one of the few rare cases of mitral valve-in-valve via a transcatheter mitral valve replacement approach with successful deployment of a SAPIEN 3 tissue heart valve. The patient experienced significant reversal of heart failure symptoms and improved exertional tolerance following deployment of the valve and was eventually discharged home in a stable condition.

Evaluation of lesion flow coefficient for the detection of coronary artery disease in patient groups from two academic medical centers.

BACKGROUND: In this study, lesion flow coefficient (LFC: ratio of % area stenosis [%AS] to the square root of the ratio of the pressure drop across the stenosis to the dynamic pressure in the throat region), that combines both the anatomical (%AS) and functional measurements (pressure and flow), was assessed for application in a clinical setting. METHODS AND RESULTS: Pressure, flow, and anatomical values were obtained from patients in 251 vessels from two different centers. Fractional flow reserve (FFR), Coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR) and hyperemic microvascular index (HMR) were calculated. Anatomical data was corrected for the presence of guidewire and the LFC values were calculated. LFC was correlated with FFR, CFR, HSR, HMR, individually and in combination with %AS. The p<0.05 was used for statistical significance. LFC correlated significantly when the FFR (pressure-based), CFR (flow-based), and anatomical measure %AS were combined (r=0.64; p<0.05). Similarly, LFC correlated significantly when HSR, HMR, and %AS were combined (r=0.72; p<0.05). LFC was able to significantly (p<0.05) distinguish between the two concordant and the two discordant groups of FFR and CFR, corresponding to the clinically used cut-off values (FFR=0.80 and CFR=2.0). The LFC could also significantly (p<0.05) distinguish between the normal and abnormal microvasculature conditions in the presence of non-significant epicardial stenosis, while the comparison was borderline significant (p=0.09) in the presence of significant stenosis. CONCLUSION: LFC, a parameter that combines both the anatomical and functional end-points, has the potential for application in a clinical setting for CAD evaluation.

Delineation of epicardial stenosis in patients with microvascular disease using pressure drop coefficient: A pilot outcome study.

AIM: To investigate the patient-outcomes of newly developed pressure drop coefficient (CDP) in diagnosing epicardial stenosis (ES) in the presence of concomitant microvascular disease (MVD). METHODS: Patients from our clinical trial were divided into two subgroups with: (1) cut-off of coronary flow reserve (CFR) < 2.0; and (2) diabetes. First, correlations were performed for both subgroups between CDP and hyperemic microvascular resistance (HMR), a diagnostic parameter for assessing the severity of MVD. Linear regression analysis was used for these correlations. Further, in each of the subgroups, comparisons were made between fractional flow reserve (FFR) < 0.75 and CDP > 27.9 groups for assessing major adverse cardiac events (MACE: Primary outcome). Comparisons were also made between the survival curves for FFR < 0.75 and CDP > 27.9 groups. Two tailed chi-squared and Fischer's exact tests were performed for comparison of the primary outcomes, and the log-rank test was used to compare the Kaplan-Meier survival curves. P < 0.05 for all tests was considered statistically significant. RESULTS: Significant linear correlations were observed between CDP and HMR for both CFR < 2.0 (r = 0.58, P < 0.001) and diabetic (r = 0.61, P < 0.001) patients. In the CFR < 2.0 subgroup, the %MACE (primary outcomes) for CDP > 27.9 group (7.7%, 2/26) was lower than FFR < 0.75 group (3/14, 21.4%); P = 0.21. Similarly, in the diabetic subgroup, the %MACE for CDP > 27.9 group (12.5%, 2/16) was lower than FFR < 0.75 group (18.2%, 2/11); P = 0.69. Survival analysis for CFR < 2.0 subgroup indicated better event-free survival for CDP > 27.9 group (n = 26) when compared with FFR < 0.75 group (n = 14); P = 0.10. Similarly, for the diabetic subgroup, CDP > 27.9 group (n = 16) showed higher survival times compared to FFR group (n = 11); P = 0.58. CONCLUSION: CDP correlated significantly with HMR and resulted in better %MACE as well as survival rates in comparison to FFR. These positive trends demonstrate that CDP could be a potential diagnostic endpoint for delineating MVD with or without ES.

Benefit of ECG-gated rest and stress N-13 cardiac PET imaging for quantification of LVEF in ischemic patients.

BACKGROUND: ECG-gated rest-stress cardiac PET can lead to simultaneous quantification of both left ventricular ejection fraction and flow impairment. In this study, our aim was to assess the benefit of rest and stress PET ejection fraction (EF) (EFp) in relation to single-photon emission computed tomography (SPECT) EF (EFs) and echocardiography EF (EFe). To this effect, the EFp was compared with EFs and EFe. Further, the relation between rest and stress EFp was also assessed. METHODS: ECG-gated N-13 ammonia rest and stress PET imaging was performed in 26 patients. EFp values were obtained using gated reconstruction of the data in Flowquant. In 13 patients, EFs and EFe values were obtained through chart review. Correlation, analysis of variance, and Bland-Altman analyses were performed. P values less than 0.05 were used for statistical significance. RESULTS: The rest and stress EFp values correlated significantly (r=0.80 and 0.71, respectively; P<0.05) with EFs values. There was moderate correlation with statistical significance (P<0.05) between the rest and stress EFp and EFe values (r=0.58 and 0.50, respectively). The mean rest and stress EFp values were not significantly different from mean EFs values. Also, the rest EFp and stress EFp values correlated well (r=0.81, P<0.05) and were not significantly different. Bland-Altman analysis showed no significant bias between the rest and stress EFp, and EFs, and EFe values. CONCLUSION: Rest and stress EFp values obtained through an ECG-gated PET scan can be used for clinical diagnosis in place of conventional methods like SPECT and echocardiography.

Lesion flow coefficient: a combined anatomical and functional parameter for detection of coronary artery disease--a clinical study.

Invasive diagnosis of coronary artery disease utilizes either anatomical or functional measurements. In this study, we tested a futuristic parameter, lesion flow coefficient (LFC, defined as the ratio of percent coronary area stenosis (%AS) to the square root of the ratio of the pressure drop across the stenosis to the dynamic pressure in the throat region), that combines both the anatomical (%AS) and functional measurements (pressure and flow) for application in a clinical setting. In 51 vessels, simultaneous pressure and flow readings were obtained using a 0.014" Combowire (Volcano Corporation). Anatomical details were assessed using quantitative coronary angiography (QCA). Fractional flow reserve (FFR), coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR), and hyperemic microvascular index (HMR) were obtained at baseline and adenosine-induced hyperemia. QCA data were corrected for the presence of guidewire and then the LFC values were calculated. LFC was correlated with FFR, CFR, HSR, and HMR, individually and in combination with %AS, under both baseline and hyperemic conditions. Further, in 5 vessels, LFC group mean values were compared between pre-PCI and post-PCI groups. P<.05 was considered statistically significant. LFC measured at hyperemia correlated significantly when the pressure-based FFR, flow-based CFR, and anatomically measured %AS were combined (r = 0.64; P<.05). Similarly, LFC correlated significantly when HSR, HMR, and %AS were combined (r = 0.72; P<.05). LFC was able to significantly distinguish between pre-PCI and post-PCI groups (0.42 ± 0.05 and 0.05 ± 0.004, respectively; P<.05). Similar results were obtained for the LFC at baseline conditions. LFC, a futuristic parameter that combines both the anatomical and functional endpoints, has potential for application in a clinical setting for stenosis evaluation, under both hyperemic and baseline conditions.

Benefit of cardiac N-13 PET CFR for combined anatomical and functional diagnosis of ischemic coronary artery disease: a pilot study.

BACKGROUND: Cardiac positron emission tomography (PET) can lead to flow impairment quantification using PET coronary flow reserve (CFRp: ratio of stress flow to rest flow) and is superior to the current standard, single-photon emission computed tomography. In this study, our first aim was to assess the benefit of CFRp in place of invasive CFR (CFRi) by comparing the correlations of each of the indices with combined pressure and flow index CDP, and combined functional (pressure-flow) and anatomical (%area stenosis, %AS) index, LFC. The second aim was to test the correlation between CFRp and CFRi. METHODS: N-13 ammonia PET scans were performed and CFRp was obtained using a 1-compartment 2K-dynamic volume (DV)-constant kinetic model in Flowquant. During catheterization, simultaneous pressure and flow readings were obtained in 10 vessels (three vessels in one patient, one vessel each in 7 patients) using a dual sensor tipped Combowire, and CFRi, CDP, LFC, and FFR were computed. %AS was obtained using quantitative coronary angiography. CDP was correlated with invasive pressure index (FFR) and CFRp and with FFR and CFRi. LFC was correlated with the %AS, FFR, and CFRp/CFRi, individually and in combination. Correlation analysis was done in SAS; p < 0.05 was used for statistical significance. RESULTS: The correlations between CDP vs FFR and CFRp (r = 0.62, p = 0.19) in combination, as well as CDP vs FFR and CFRi in combination (r = 0.58, p = 0.24) remained similar. The correlation between LFC vs FFR, CFRp and %AS in combination improved (r = 0.82) with a near-significant p = 0.06, in comparison to the correlation between LFC vs FFR, CFRi and %AS in combination (r = 0.75, p = 0.15). CFRp correlated strongly and significantly (r = 0.82, p = 0.003) with CFRi, and the values were within 11 %. CONCLUSION: The novelty of the PET procedure in this study is that the noninvasive CFRp can be used instead of invasive CFRi for the functional diagnosis of CAD. Therefore, a PET scan can reduce procedure time and cost while simplifying the diagnostic protocol for assessing coronary artery disease, thus benefitting both the patients and clinicians.

Diagnostic performance of pressure drop coefficient in relation to fractional flow reserve and coronary flow reserve.

OBJECTIVES AND BACKGROUND: Functional assessment of coronary lesion severity during cardiac catheterization is conducted using diagnostic parameters like fractional flow reserve (FFR; pressure derived) and coronary flow reserve (CFR; flow derived). However, the complex hemodynamics of stenosis might not be sufficiently explained by either pressure or flow alone, particularly in the case of intermediate stenosis. CDP (ratio of pressure drop across a stenosis to distal dynamic pressure), a non-dimensional index derived from fundamental fluid dynamic principles based on a combination of intracoronary pressure and flow, may improve the functional assessment of coronary lesion severity. METHODS: We performed a meta-analysis of seven studies, retrieved from MEDLINE and PubMed, comparing the results of FFR and CFR of the same lesions. Two studies reported functional measurements (pressure and flow) obtained in individual patients. Five studies reported two-dimensional plots of FFR vs. CFR. The FFR and CFR data were digitized and corresponding functional measurements were extracted using the reported mean values of hemodynamic data from each of the five studies. The receiver operating characteristic (ROC) curve was used to identify the optimal cut-off point of CDP, which corresponds to the clinically used cut-off values (FFR = 0.80, FFR = 0.75, and CFR = 2.0). RESULTS: CDP correlated significantly with FFR (r = 0.78; P<.001) and had significant diagnostic efficiency (area under the ROC curve = 89%), specificity (83% and 85%), and sensitivity (81% and 76%) at FFR <0.8 and FFR <0.75, respectively. The corresponding cut-off value for CDP to detect FFR <0.80 and FFR <0.75 was at CDP >27.1 and CDP >27.9, respectively. CONCLUSIONS: CDP, a functional parameter based on both intracoronary pressure and flow measurements, has close agreement (area under the ROC curve = 89%) with FFR, the most frequently used method for evaluation of coronary stenosis severity.

Effect of myocardial contractility on hemodynamic end points under concomitant microvascular disease in a porcine model.

In this study, coronary diagnostic parameters, pressure drop coefficient (CDP: ratio of trans-stenotic pressure drop to distal dynamic pressure), and lesion flow coefficient (LFC: ratio of % area stenosis (%AS) to the CDP at throat region), were evaluated to distinguish levels of %AS under varying contractility conditions, in the presence of microvascular disease (MVD). In 10 pigs, %AS and MVD were created using angioplasty balloons and 90-µm microspheres, respectively. Simultaneous measurements of pressure drop, left ventricular pressure (p), and velocity were obtained. Contractility was calculated as (dp/dt)max, categorized into low contractility <900 mmHg/s and high contractility >900 mmHg/s, and in each group, compared between %AS <50 and >50 using analysis of variance. In the presence of MVD, between the %AS <50 and >50 groups, values of CDP (71 ± 1.4 and 121 ± 1.3) and LFC (0.10 ± 0.04 and 0.19 ± 0.04) were significantly different (P < 0.05), under low-contractility conditions. A similar %AS trend was observed under high-contractility conditions (CDP: 18 ± 1.4 and 91 ± 1.4; LFC: 0.08 ± 0.04 and 0.25 ± 0.04). Under MVD conditions, similar to fractional flow reserve, CDP and LFC were not influenced by contractility.

Functional diagnosis of coronary stenoses using pressure drop coefficient: a pilot study in humans.

OBJECTIVES AND BACKGROUND: Myocardial fractional flow reserve (FFR) in conjunction with coronary flow reserve (CFR) is used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between FFR and CFR have been observed in intermediate coronary lesions. A functional parameter, pressure drop coefficient (CDP; ratio of pressure drop to distal dynamic pressure), was assessed using intracoronary pressure drop (dp) and average peak velocity (APV). The CDP is a nondimensional ratio, derived from fundamental fluid dynamic principles. We sought to evaluate the correlation of CDP with FFR, CFR, and hyperemic stenosis resistance (HSR: ratio of pressure drop to APV) in human subjects. METHODS: Twenty-seven patients with reversible perfusion defects based on SPECT were consented for the study before cardiac catheterization. Distal coronary pressure and APV were measured simultaneously for each coronary lesion using a Combowire(©) during cardiac catheterization. Reference diameter, minimal lumen diameter, and %AS were obtained by quantitative coronary angiography. Maximum hyperemia was induced by IV adenosine (140 µg/kg/min). CDP was calculated as, (Δp)/(0.5 × ρ × APV(2) ). The density of blood (ρ) was assumed to be 1.05 gm/cm(3) . RESULTS: The functional index, CDP, when correlated simultaneously with FFR and CFR, was found to have a significant correlation (r = 0.61; P < 0.05). Similarly a significant correlation was achieved when CDP was correlated with HSR (r = 0.91; P < 0.001). This is consistent with the definition of CDP, which is a functional parameter that includes both pressure and flow information. CONCLUSIONS: CDP, a nondimensional parameter combining simultaneous measurements of pressure drop and velocity data, can accurately define the severity of coronary stenoses and could prove advantageous clinically.

Impact of kissing balloon inflation on the main vessel stent volume, area, and symmetry after side-branch dilation in patients with coronary bifurcation lesions: a serial volumetric intravascular ultrasound study.

OBJECTIVES: Intravascular ultrasound (IVUS) was performed to investigate the impact of kissing balloon inflation (KBI) on the main vessel (MV) stent volume, area, and symmetry after side-branch (SB) dilation in patients with coronary bifurcation lesions (CBL). BACKGROUND: It remains controversial whether KBI would restore the MV stent area and symmetry loss after SB dilation. METHODS: A total of 88 serial IVUS examinations of the MV were performed after MV angioplasty, MV stenting, SB dilation, and KBI in 22 patients with CBL. The MV stent was divided into proximal, bifurcation, and distal segments; the stent volume index (SVI), minimal stent area (MSA), stent symmetry index (SSI), and external elastic membrane (EEM) volume index were measured in 198 stent segments and compared after MV stenting, SB dilation, and KBI. RESULTS: In the bifurcation segment, SVI, MSA, and SSI were significantly smaller after SB dilation than after MV stenting and KBI (SVI was 6.10 ± 1.50 mm(3)/mm vs. 6.68 ± 1.60 mm(3)/mm and 6.57 ± 1.60 mm(3)/mm, respectively, p < 0.05; MSA was 5.15 ± 1.30 mm(2) vs. 6.08 ± 1.40 mm(2) and 5.86 ± 1.50 mm(2), respectively, p < 0.05; and SSI was 0.78 ± 0.02 mm(2) vs. 0.87 ± 0.03 mm(2) and 0.84 ± 0.03 mm(2), respectively, p < 0.05). KBI restored the MV SVI, MSA, and SSI after SB dilation. In the proximal segment, SVI, MSA, and EEM volume index were significantly larger, but SSI was smaller after KBI than after MV stenting and SB dilation. In the distal segment, neither SB dilation nor KBI had a significant impact on the MV stent volume or symmetry. CONCLUSIONS: This is the first comprehensive volumetric IVUS analysis of CBL, to our knowledge, demonstrating that KBI restores the MV stent volume, area, and symmetry loss after SB dilation in the bifurcation segment, and induces asymmetric stent expansion in the proximal segment.

Congenital anastomosis between left anterior mammary and pulmonary vasculatures.

Several case reports have described the presence of acquired fistula connecting the left internal mammary artery to the pulmonary vasculature; however, occurrence of this type of congenital fistulas is less common. The authors present a case of a congenital left internal mammary artery-pulmonary vasculature fistula that was incidentally found during a coronary angiography in a patient who was being evaluated for coronary artery bypass surgery. The particulars of the case are discussed, and the literature is reviewed.

Effect of changes in contractility on pressure drop coefficient and fractional flow reserve in a porcine model.

OBJECTIVES AND BACKGROUND: Decisions based on invasive functional diagnostic measurements are often made in the setting of fluctuating hemodynamic variables that may alter resting or hyperemic measurements. The purpose of this investigation is to analyze the effect of myocardial contractility (CY) on invasive functional parameters. We hypothesize that the pressure drop coefficient (CDPe; ratio of pressure drop to distal dynamic pressure) and fractional flow reserve (FFR; ratio of average pressures distal and proximal to a stenosis) are not affected by fluctuations in CY and can distinguish between different severities of epicardial stenosis. METHODS: Simultaneous measurements of distal coronary-arterial pressure and velocity were performed in 10 pigs using a dual-sensor tipped guidewire for heart rate (HR) <110 bpm and HR >110 bpm, in the presence of coronary lesions of <50% area stenosis (AS) and >50% AS. Variations in myocardial function and vascular resistance were induced by atrial pacing, papaverine and balloon obstruction, respectively. The maximum rate of rise of left ventricular pressure ([dp/dt]max) was the index of contractility. The contractile function of the heart was empirically defined as CY >900 mm Hg/sec (higher) and CY <900 mm Hg/sec (normal). RESULTS: For CY >900 mm Hg/sec, under AS <50% and AS >50%, the mean values of FFR (0.91 ± 0.02 and 0.78 ± 0.02), and CDPe (15.6 ± 5.3 and 70.7 ± 24.7) were significantly different (P<.05). Similarly, for CY <900 mm Hg/sec, under AS <50% and AS >50%, the mean values of FFR (0.83 ± 0.04 and 0.63 ± 0.04), and CDPe (43.8 ± 14.9 and 191.8 ± 61.4) were also significantly different (P<.05). CONCLUSIONS: Both FFR and CDPe could effectively distinguish between stenosis severity at normal and higher levels of myocardial contractility.

Safety and efficacy of drug eluting stents compared with bare metal stents for saphenous vein graft interventions: a comprehensive meta-analysis of randomized trials and observational studies comprising 7,994 patients.

BACKGROUND: Saphenous vein graft (SVG) lesions remain amongst the most challenging lesions for percutaneous coronary intervention (PCI). It is unknown whether drug eluting stents (DES) are superior to bare metal stents (BMS) for such lesions. Our objective is to determine the safety and efficacy of DES compared with BMS for SVG lesions by performing a meta-analysis of clinical trials and observational studies. DATA SOURCES: PubMed, Cochrane Register of Controlled Trials, conference proceedings, and internet-based resources of clinical trials. STUDY SELECTION: Studies comparing DES vs. BMS for SVG lesions with at least>30 patients in each study reporting the outcomes of interest [death, myocardial infarction (MI), target vessel revascularization (TVR), stent thrombosis (ST), and the composite of death, TVR and MI (major adverse cardiac events; MACE)] with at least 6 months clinical follow-up. The primary outcome of interest was death. RESULTS: Two randomized trials, one subgroup analysis of a randomized trial and 26 observational studies comprising a total of 7,994 patients (4,187 patients in DES and 3,807 patients in BMS group) were included in the analysis. Mean follow-up duration was 21±11 months (6-48 months). In the overall population, MACE events were 19% in DES and 28% in BMS with a risk ratio (RR) of 0.7 (0.6, 0.8) P<0.00001. This effect of MACE was sustained in studies with >2 years follow-up with RR of 0.77 (0.65, 0.91) P=0.003. Death rate was 7.8% in DES and 9% in BMS with a RR of 0.82 (0.7, 0.97) P=0.02. MI rate was 5.7% in DES and 7.6% in BMS with RR of 0.72 (0.57, 0.91) P=0.007. TVR was 12% in DES and 17% in BMS with RR of 0.71 (0.59, 0.85) P=0.0002. ST was 1% in DES and 1.7 % in BMS RR of 0.61 (0.35, 1.06) P=0.08. Specifically in randomized controlled trials, DES were associated with no significant differences in overall mortality [RR=1.97; 95% confidence interval (CI), 0.17-23; P=0.58] or MI (RR=1.24; 95% CI, 0.3-5.5; P=0.78) compared with BMS. CONCLUSIONS: Based on the results of this meta-analysis, DES may be considered as a safe and efficacious option for the percutaneous intervention of SVG lesions.

Influence of heart rate on fractional flow reserve, pressure drop coefficient, and lesion flow coefficient for epicardial coronary stenosis in a porcine model.

A limitation in the use of invasive coronary diagnostic indexes is that fluctuations in hemodynamic factors such as heart rate (HR), blood pressure, and contractility may alter resting or hyperemic flow measurements and may introduce uncertainties in the interpretation of these indexes. In this study, we focused on the effect of fluctuations in HR and area stenosis (AS) on diagnostic indexes. We hypothesized that the pressure drop coefficient (CDP(e), ratio of transstenotic pressure drop and distal dynamic pressure), lesion flow coefficient (LFC, square root of ratio of limiting value CDP and CDP at site of stenosis) derived from fluid dynamics principles, and fractional flow reserve (FFR, ratio of average distal and proximal pressures) are independent of HR and can significantly differentiate between the severity of stenosis. Cardiac catheterization was performed on 11 Yorkshire pigs. Simultaneous measurements of distal coronary arterial pressure and flow were performed using a dual sensor-tipped guidewire for HR < 120 and HR > 120 beats/min, in the presence of epicardial coronary lesions of <50% AS and >50% AS. The mean values of FFR, CDP(e), and LFC were significantly different (P < 0.05) for lesions of <50% AS and >50% AS (0.88 ± 0.04, 0.76 ± 0.04; 62 ± 30, 151 ± 35, and 0.10 ± 0.02 and 0.16 ± 0.01, respectively). The mean values of FFR and CDP(e) were not significantly different (P > 0.05) for variable HR conditions of HR < 120 and HR > 120 beats/min (FFR, 0.81 ± 0.04 and 0.82 ± 0.04; and CDP(e), 95 ± 33 and 118 ± 36). The mean values of LFC do somewhat vary with HR (0.14 ± 0.01 and 0.12 ± 0.02). In conclusion, fluctuations in HR have no significant influence on the measured values of CDP(e) and FFR but have a marginal influence on the measured values of LFC. However, all three parameters can significantly differentiate between stenosis severities. These results suggest that the diagnostic parameters can be potentially used in a better assessment of coronary stenosis severity under a clinical setting.

Fibrinolytic therapy for very late stent thrombosis--is it a viable option?

Stent thrombosis (ST) has a very high case fatality and morbidity rates. The risk of very late ST is significantly increased with drug-eluting stents (DES) compared to bare-metal stents for at least up to 4 years. Discontinuation of clopidogrel therapy is the single most important consistently identified risk factor. Immediate reperfusion, preferably by primary percutaneous coronary intervention (PCI), has been considered the therapy of choice. Compared to de novo ST-elevation myocardial infarction (STEMI), myocardial infarction (MI) related to ST has significantly higher major adverse cardiovascular events (MACE) and lower reperfusion rates. Due to the significantly higher mortality associated with STEMI due to ST, prompt revascularization assumes paramount significance. Our case reflects the potential utility of fibrinolytic therapy for STEMI due to very late ST. Systemic fibrinolysis should be considered for ST in the presence of ongoing significant ischemia and unavailability of prompt PCI.

Novel use of twin-pass catheter in successful recanalization of a chronic coronary total occlusion.

One of the most difficult challenges in interventional cardiology has been in finding the approach to treat chronic total occlusions (CTOs). Here we present a case of recanalization of an angulated, calcified CTO. The lesion presented difficulty due to the lack of guidewire support to facilitate crossing of the CTO. In our case, an uncommon approach using a dual-lumen catheter (Twin-Pass) to support and direct a guidewire was attempted. This resulted in a successful percutaneous revascularization.