Safety and efficacy of the INC bioprosthetic heart valve in humans

INTRODUCTION

Heart valve bioprostheses are the gold standard for aortic valve surgical replacement in selected patients.

OBJECTIVE

To evaluate the safety and efficacy of the National Institute of Cardiology (INC) bioprosthetic heart valve in humans.

METHODS

Single-center study that included 341 patients who underwent single surgical aortic valve replacement with INC heart valve.

RESULTS

318 implants were performed de novo (93%) and 23 as redo surgery (7%); STS scores were 1.4 and 1.8%, and follow-up was for 42 and 46 months, respectively. There were no differences in clinical complications or pacemaker implantation rate. Both groups maintained a normal LVEF. Overall improvement in functional class was observed, with worsening only in two patients of the de novo group. INC prosthesis dysfunction requiring surgical reintervention was observed in eight patients (4.65%) of the de novo group vs. one patient in the redo group.

CONCLUSIONS

The INC heart valve is efficacious and safe, and is associated with a low rate of complications and functional class improvement during long-term follow-up. Prospective, comparative studies of this valve are required.

Evaluation of an automatized AMBU ESSI-1 INC designed at the Instituto Nacional de Cardiología Ignacio Chávez

OBJECTIVE

The objectives of this study were to evaluate an automated device for ventilatory support based on AMBU manufactured in March 2020.

METHODS

The ESSI-1 INC was evaluated through pulmonary mechanics and physiology parameters through compensatory spirometer tests (TISSOTs), and an artificial lung Model5600i Dual Adult PNEU VIEW SYSTEM; it was also compared to the anesthetic ventilatory support equipment (AEONMED 7500) in porcine models, measuring ventilatory, hemodynamic and gasometric parameters.

RESULTS

This equipment (ESSI-1 INC) was successfully tested by mechanical and biological models, such as pigs in which its performance was evaluated in terms of variability of tidal volume, ventilation frequency, and I/E relationship versus the manual performance of two medical interns. All the results turned out as expected and were satisfactory.

CONCLUSIONS

It is safe and effective equipment and should be tested and used in diverse clinical conditions to standardize the ventilatory safety and care of patients who require it.

The rs4783961 and rs708272 genetic variants of the CETP gene are associated with coronary artery disease, but not with restenosis after coronary stenting

Objective:

We evaluated whether cholesteryl ester transfer protein (CETP) gene polymorphisms are associated with the presence of coronary artery disease (CAD) and/or restenosis in patients with coronary stent.

Methods:

Two polymorphisms of the CETP gene [−971 A/G (rs4783961), and Taq1B A/G (rs708272)] were genotyped by 5’exonuclease TaqMan assays in 219 patients with CAD (66 patients with restenosis and 153 without restenosis) and 607 control individuals.

Results:

The distribution of polymorphisms was similar in patients with and without restenosis. However, when the whole group of patients (with and without restenosis) was compared to healthy controls, under dominant model, the G allele of the Taq1B A/G polymorphism was associated with increased risk of CAD (odds ratio [OR] = 1.48, pC_Dom = 0.032). In the same way, under codominant, dominant, and additive models, the A allele of the −971 A/G polymorphisms was associated with an increased risk of developing CAD (OR = 2.03, pC_Co-dom = 0.022, OR = 1.83, pC_Dom = 0.008, and OR = 1.39, pC_Add = 0.011, respectively). In addition, the linkage disequilibrium showed that the “AG” haplotype was associated with increased risk of developing CAD (OR = 1.28, p = 0.03).

Conclusion:

This study demonstrates that CETP Taq1B A/G and CETP −971 A/G polymorphisms are associated with an increased risk of developing CAD, but no association with restenosis was observed.

Design and manufacture of a coronary stent INC-1 and initial tests in experimental animal model

In this paper, we describe our coronary stent (INC-1) design and development, the way that we found the specific characteristics needed for our device including biophysics aspects, design, finite element testing, manufacturing, and mechanic trials, we submitted and animal models experiences. The stent platform was cobalt-chromium L605 (Co-Cr), with struts thickness of 80 μm, balloon expandable. We placed the coronary stent INC-1 on a rabbit and dog models so we can evaluate efficacy and security of the device in relationship to its biomechanical properties including navigation capacity, traceability, symmetric expansion, and safety, as well as endothelial attachment, thrombogenicity, and lack of involvement of secondary branches in these models. We succeeded in efficacy and safety of the device after fluoroscopy-guided implant proving excellent capacity of release system, traceability, fluoroscopic visualization, symmetric expansion, and complete endothelial attach. Furthermore, we obtained a good post-implant balloon withdrawal, functional integrity, and no vascular complications. We observed adequate clinical evolution 3 weeks after the stent implantation.

Design, manufacture and initial tests of a drug-eluting coronary stent

Introduction

A drug-eluting coronary stent is being developed at the National Institute of Cardiology of Mexico for the treatment of ischemic heart disease.

Objective

To establish the best animal model for the tests, to show the advances in the drug-eluting stent prototype, to assess two drugs' antiproliferative activity and histological results.

Method

Smooth muscle cell culture tests were performed in order to assess sirolimus and paclitaxel antiproliferative properties. The drugs were encapsulated inside the polymeric matrix of the stents. Rabbits and pigs were used as animal models.

Results

Sirolimus and paclitaxel showed an inhibitory effect, which was higher for the latter. Infrared spectroscopy and light and optical microscopy showed that the drug/polymer layer properly adhered to the stent. At a four-week follow-up, both animal models showed satisfactory clinical evolution and adequate histological response, although the porcine model was shown to be more suitable for future protocols.

Conclusions

Preliminary tests of the drug-eluting stent provided bases for the development of a study protocol with an adequate number of pigs and with clinical angiographic and histopathological three-month follow-up.

Design and manufacture of a coronary stent INC-1 and initial tests in experimental animal model

In this paper we describe our coronary stent (INC-1) design and development, the way that we found the specific characteristics needed for our device including biophysics aspects, design, finite element testing, manufacturing and mechanic trials we submitted and animal models experiences. The stent platform was cobalt-chromium L605 (Co-Cr), with struts thickness of 80 µm, balloon expandable. We placed the coronary stent INC-1 on a rabbit and dog models so we can evaluate efficacy and security of the device in relationship to its biomechanical properties including navigation capacity, traceability, symmetric expansion and safety. As well as endothelial attachment, thrombogenicity and lack of involvement of secondary branches in these models. We succeeded in efficacy and safety of the device after fluoroscopy-guided implant proving excellent capacity of release system, traceability, fluoroscopic visualization, symmetric expansion and complete endothelial attach. Also, we obtained a good post-implant balloon withdrawal, functional integrity and no vascular complications. We observed adequate clinical evolution 3 weeks after the stent implantation.

THE BRANCHED-CHAIN AMINO ACID TRANSAMINASE 1 -23C/G POLYMORPHISM CONFERS PROTECTION AGAINST ACUTE CORONARY SYNDROME

Background

Previous studies have shown an association between polymorphisms of the BAT1-NF-κB inhibitor-like-1 (NFKBIL1)-LTA genomic region and susceptibility to myocardial infarction and acute coronary syndrome (ACS).

Objective

The objective of the study was to study the role of three polymorphisms in the BAT1, NFKBIL1, and LTA genes on the susceptibility or protection against ACS; we included a group of cases-controls from Central Mexico.

Methods

The BAT1 rs2239527C/G, NFKBIL1 rs2071592T/A, and LTA rs1800683G/A polymorphisms were genotyped using a 5' TaqMan assay in a group of 625 patients with ACS and 617 healthy controls.

Results

Under a recessive model, the BAT1 -23C/G (rs2239527) polymorphism showed an association with protection against ACS (odds ratio = 0.56, and p-corrected = 0.019). In contrast, the genotype and allele frequencies of the NFKBIL1 rs2071592T/A and LTA rs1800683G/A polymorphisms were similar between ACS patients and controls and no association was identified.

Conclusion

Our data suggest an association between the BAT1 -23C/G polymorphism and protection against ACS in Mexican patients.

HUMAN PILOT STUDY OF BARE-METAL STENT: INC-01

Background

The cost of performing a percutaneous coronary intervention is considerably high for the patient as well as for health systems, which have promoted the development of local technology to help meet the need for these devices.

Methods

The INC-01 bare-metal stent was developed at the National Institute of Cardiology in Mexico City and was first implanted on porcine models with technical success in 100% of the evaluated parameters.

Presentation of Cases

We present the first three cases of patients with ischemic heart disease, to whom the INC-01 bare-metal stent was implanted. Intracoronary ultrasonography was performed post-stent implantation, showing all the characteristics of implant success during evaluation and clinical follow-up.

Conclusions

Angiography and intracoronary ultrasound were carried out demonstrating that the INC-01 bare-metal stent has physical, biological, and histological characteristics similar to those found in commercial metallic stents.

[Deferred versus immediate stenting in patients with ST - segment elevation myocardial infarction and residual large thrombus burden reclassified in the culprit lesion]

BACKGROUND

Reclassification of a large thrombus burden is an independent predictor of major adverse cardiac events and no-reflow in patients with ST- segment elevation myocardial infarction (STEMI). Patients with a greater residual thrombus burden have worse microvascular dysfunction and greater myocardial damage.

METHODS

A retrospective analysis was performed on 833 STEMI patients who underwent primary percutaneous coronary intervention. The final residual thrombus burden was reclassified after the lesion was wired, and a thrombus aspiration or balloon dilatation was performed to restore and stabilise a thrombolysis in myocardial infarction (TIMI) 2-3 flow. Deferred stenting (DEI) was compared with immediate stenting (ISI) group, and the primary outcome was the incidence of no-/slow-reflow (TIMI ≤ 2, or TIMI 3 with myocardial blush grade < 2).

RESULTS

Overall, 47 patients (6.8%) had a residual large thrombus burden reclassified. The right coronary artery was the culprit vessel in 34 cases. More patients had coronary ectasia in the DSI group (P=.005). Fewer patients in the DSI had no-/slow-reflow (36% vs. 58%), and the myocardial blush grade 3 was more frequent in the DSI group (P=.005). After repeat coronary angiography in the DSI group, stenting was not performed in 56%, and oral anticoagulation was more frequent in the follow-up (P=.031). Major cardiac adverse events were similar between groups. There was a tendency to better left ventricular function in the DSI group (P=.056).

CONCLUSIONS

Deferred stenting may be an efficient option in STEMI patients with a residual large thrombus burden reclassified after achieving a stable TIMI 2-3 flow.

Heart and brain interaction in patients with heart failure: overview and proposal for a taxonomy. A position paper from the Study Group on Heart and Brain Interaction of the Heart Failure Association

Heart failure (HF) is a complex clinical syndrome with multiple interactions between the failing myocardium and cerebral (dys-)functions. Bi-directional feedback interactions between the heart and the brain are inherent in the pathophysiology of HF: (i) the impaired cardiac function affects cerebral structure and functional capacity, and (ii) neuronal signals impact on the cardiovascular continuum. These interactions contribute to the symptomatic presentation of HF patients and affect many co-morbidities of HF. Moreover, neuro-cardiac feedback signals significantly promote aggravation and further progression of HF and are causal in the poor prognosis of HF. The diversity and complexity of heart and brain interactions make it difficult to develop a comprehensive overview. In this paper a systematic approach is proposed to develop a comprehensive atlas of related conditions, signals and disease mechanisms of the interactions between the heart and the brain in HF. The proposed taxonomy is based on pathophysiological principles. Impaired perfusion of the brain may represent one major category, with acute (cardio-embolic) or chronic (haemodynamic failure) low perfusion being sub-categories with mostly different consequences (i.e. ischaemic stroke or cognitive impairment, respectively). Further categories include impairment of higher cortical function (mood, cognition), of brain stem function (sympathetic over-activation, neuro-cardiac reflexes). Treatment-related interactions could be categorized as medical, interventional and device-related interactions. Also interactions due to specific diseases are categorized. A methodical approach to categorize the interdependency of heart and brain may help to integrate individual research areas into an overall picture.

Toll-like receptor 4 gene polymorphisms and acute coronary syndrome: no association in a Mexican population

OBJECTIVE

The objective of this study was to establish the role of the TLR-4 gene polymorphisms in individuals in risk of developing ACS.

METHODS

The study included 457 Mexican patients with ACS and 283 control individuals. The TLR-4 Asp299Gly and TLR-4 Thr399Ile single nucleotide polymorphisms were genotyped using 5' exonuclease TaqMan genotyping assays on an 7900HT Fast real-time PCR system according to manufacturer's instructions (Applied Biosystems, Foster City, USA).

RESULTS

The results obtained in this study showed that the frequency of the two polymorphisms (TLR-4 Asp299Gly and TLR-4 Thr399Ile) studied were similar between patients with ACS and healthy controls. Multiple logistic regression analysis showed that the largest risk factor for ACS development was given by smoking (11.88-fold increased risk), hypertension (4.32-fold increased risk), type II diabetes (3.44-fold increased risk), gender (2.32-fold increased risk), and dyslipidemia (1.52-fold increased risk).

CONCLUSION

The Asp299Gly and Thr399Ile polymorphisms were not associated with susceptibility to ACS in the Mexican population.

Homocysteine is related to aortic mineralization in patients with ischemic heart disease

Homocysteine is implicated as an early atherosclerotic promoter, which enhances the smooth muscle cell proliferation and produces free radicals that induce cellular damage. These factors must have a role in the progression of atherosclerosis that subsequently leads to vascular mineralization.

AIM

Identify a correlation between the plasma concentration of total homocysteine and the amount of minerals that accumulate in the aorta of patients with atherosclerosis.

METHODS

We performed a cross-sectional study in 13 patients with three-vessel coronary artery disease, undergoing coronary artery bypass surgery. Aortic and mammary artery specimens were analyzed using a scanning electron microscope with an energy dispersive X-ray spectrometer. The homocysteine was determined using an immunonephelometry method.

RESULTS

The amount of minerals in the aorta was greater (300 ± 181.6 particles per 500 µm2 than that in the mammary artery (64 ± 45 particles per 500 µm2 (p < 0.01). The average tHcy was 9.5 ± 2.3 µmol/L. The Spearman's rank correlation coefficient was positive between tHcy, and aortic iron (p < 0.05).

CONCLUSIONS

Our study demonstrates that the aorta is dramatically affected by mineralization compared to the mammary artery. In addition, a direct correlation was identified between the levels of tHcy and the iron particles in the aortic wall.

Design and implementation of the TRACIA: intracoronary autologous transplant of bone marrow-derived stem cells for acute ST elevation myocardial infarction

OBJECTIVE

To describe the design of a protocol of intracoronary autologous transplant of bone marrow-derived stem cells for acute ST-elevation myocardial infarction (STEMI) and to report the safety of the procedure in the first patients included.

METHODS

The TRACIA study was implemented following predetermined inclusion and exclusion criteria. The protocol includes procedures such as randomization, bone marrow retrieval, stem cells processing, intracoronary infusion of stem cells in the infarct-related artery, preand- post MRI, pre-and-post SPECT with radioisotope ventriculography, and clinical follow-up at 6 months.

RESULTS

Eight patients with a diagnosis of acute STEMI and duration of symptoms of ?24 hours that were perfused successfully through primary percutaneous coronary intervention (PPCI) with a LVEF of ?45% were assigned randomly to two groups (n = 4 each). One group treated with stem cells and the other corresponded to the control group. Neither death, re-infarction, no need for revascularization or thrombosis of the stent were observed at follow-up.

CONCLUSIONS

The initial experience at the Instituto Nacional de Cardiología Ignacio Chávez in the treatment of acute STEMI by means of autologous transplantation of bone marrow-derived stem cells is encouraging. Implementation was possible in the first eight patients with no complications.

Comparison of reperfusion regimens with or without tirofiban in ST-elevation acute myocardial infarction

There is continued debate as to whether a combined reperfusion regimen with platelet glycoprotein IIb/IIIa inhibitors provides additional benefit in optimal myocardial reperfusion of patients with a ST-elevation acute myocardial infarction (AMI). In addition, the best angiographic method to evaluate optimal myocardial reperfusion is still controversial. Patients (n = 144) with a first AMI presenting <6 hours from onset of symptoms were randomized to receive a conjunctive strategy (n = 72) with low-dose alteplase (50 mg) and tirofiban (0.4 microg/kg/min/30 minute bolus; infusion of 0.1 microg/kg/minute), or tirofiban plus stenting percutaneous coronary intervention (PCI). Control patients (n = 72) received standard strategy with either full-dose alteplase (100 mg) or stenting PCI [correction]. All patients were submitted to coronary angiographic study at 90 minutes. The primary end point was Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow at 90 minutes. Secondary end points were TIMI myocardial perfusion (TMP) rates, a composite end point at 30 days (death, reinfarction, refractory ischemia, stroke, heart failure, revascularization procedures, or pulmonary edema), and bleeding or hematologic variables. The rate of TIMI 3 flow at 90 minutes for patients treated with alteplase alone was 42% compared with 64% for those who received low-dose alteplase and tirofiban. Standard stenting PCI achieved 81% of TIMI 3 flow compared with 92% when tirofiban was used. Significantly higher rates of TMP grade 3 were observed when tirofiban was used as the adjunctive treatment in both alteplase (66% vs 47%) and stenting PCI (73% vs 55%). Higher rates of the composite end point were observed in standard regimens compared with conjunctive regimens (hazard ratio 5.8, 95% confidence interval 1.27 to 26.6, p = 0.023). Regardless of reperfusion regimen, better outcomes were observed when a combination of TIMI 3 flow and TMP grade 3 was achieved. Beyond TIMI 3 flow rate, the TMP grade was an important determinant. The rates of major bleeding were similar (2.8%) for standard versus conjunctive regimens with tirofiban. Thus, tirofiban as a conjunctive therapy for lytic and stenting regimens not only improves TIMI 3 flow rates, but also the TMP3 rates, which are related to a better clinical outcome without an increase in the risk of major bleeding. This study supports the hypothesis that platelets play a key role not only in the atherothrombosis process, but also in the disturbances of microcirculation and tissue perfusion.

Comparative trial of stent-like balloon angioplasty versus coronary stenting for acute myocardial infarction

Primary PTCA has been shown to be superior to any thrombolytic regimen and offers higher reperfusion rates and better coronary flow grades. Its limitations include recurrent ischemia (10%-15%), infarct-related artery reocclusion (5%-10%), angiographic restenosis (35%-50%), and need to perform repeat PTCA or CABG at 6-month follow-up (20%). Thus, the current role of coronary stenting for acute myocardial infarction (AMI) is very promising. From December 1995 through January 1997, 335 patients underwent primary angioplasty during the first 12 hr from symptom onset at our institution. We performed a retrospective study comparing the in-hospital and 6-month follow-up outcome of 61 patients who underwent coronary stenting (stent group) against 61 patients with optimal (residual lesion stenosis < 30%) balloon-only primary angioplasty (stent-like group). Patients were routinely treated with aspirin, and ticlopidine was given only to the stent group. In-hospital major adverse cardiac events (MACE) rate was 11.5% without statistical differences between the groups. Cardiac death rate was similar in both groups (4.9 vs. 6.6%; P = 1.0) and only two (3.3%) patients from the stent group and none from the PTCA group had nonfatal myocardial reinfarction. At 6-month follow-up, the rate of recurrent angina was higher in the stent-like group (30.9 vs. 7.1%; P < 0.001). Multivariate analysis showed that only stenting of the infarct-related artery was a borderline independent predictor for MACE (OR = 0; 95% CI = 0-1; P = 0.057). Primary stenting for AMI reduces the rate of recurrent angina or symptoms and MACE at 6-month follow-up.

[The no-reflow phenomenon: its incidence and clinical characteristics in a series of cases]

The no-reflow phenomenon refers to the inability to reperfuse myocardial tissue despite removal of an occlusion of a coronary artery. No reflow is a complication that may occur after revascularization of patients. This study examined the incidence and, clinical characteristics of no-reflow in a patient population treated with conventional percutaneous transluminal coronary angioplasty at the Instituto Nacional de Cardiología "Ignacio Chávez". We reviewed 204 elective angioplasties and 62 direct angioplasties; 14 patients were included (4 from the first group and 10 from the second group). No-reflow were more frequently in men, the mean age was 56 years and diabetes and smoking were the risk factors more frequently reported. No-reflow was found in left anterior descending coronary artery in 7 patients, the time of reperfusion, in direct angioplasty, was 10.6 hours (mean) and the strategy most frequently used to reestablish normal anterograde flow was intracoronary verapamil. The overall incidence of no-reflow for the two modalities was 5.2% (16.12% for direct angioplasty and 1.9% for elective angioplasty). The current study shows that the no-reflow phenomenon is not uncommon after angioplasty; no-reflow appears higher than the previous reports for both modalities of treatment.