Cerebral emboli detection and autonomous neuromonitoring using robotic transcranial Doppler with artificial intelligence for transcatheter aortic valve replacement with and without embolic protection devices: a pilot study

BACKGROUND

Periprocedural ischemic stroke remains a serious complication in patients undergoing transcatheter aortic valve replacement (TAVR). We used a novel robotic transcranial Doppler (TCD) system equipped with artificial intelligence (AI) for real-time continuous intraoperative neuromonitoring during TAVR to establish the safety and potential validity of this tool in detecting cerebral emboli, report the quantity and distribution of high intensity transient signals (HITS) with and without cerebral protection, and correlate HITS occurrence with various procedural steps.

METHODS

Consecutive patients undergoing TAVR procedures during which the robotic system was used between October 2021 and May 2022 were prospectively enrolled in this pilot study. The robotic TCD system included autonomous adjustment of the TCD probes and AI-assisted post-processing of HITS and other cerebral flow parameters. Basic demographics and procedural details were recorded. Continuous variables were analyzed by a two-sample Mann-Whitney t-test and categorical variables by a χ2 or Fisher test.

RESULTS

Thirty-one patients were prospectively enrolled (mean age 79.9±7.6 years; 16 men (51.6%)). Mean aortic valve stenotic area was 0.7 cm2 and mean aortic-ventricular gradient was 43 mmHg (IQR 31.5-50 mmHg). Cerebral protection was used in 16 cases (51.6%). Significantly fewer emboli were observed in the protection group than in the non-protection group (mean 470.38 vs 693.33; p=0.01). Emboli counts during valve positioning and implantation were significantly different in the protection and non-protection groups (mean 249.92 and 387.5, respectively; p=0.01). One (4%) transient ischemic attack occurred post-procedurally in the non-protection group.

CONCLUSION

We describe a novel real-time intraoperative neuromonitoring tool used in patients undergoing TAVR. Significantly fewer HITS were detected with protection. Valve positioning-implantation was the most significant stage for intraprocedural HITS.

A Case of Unintentional Release of the Watchman FLX Device During Implantation: A Cautionary Tale

Atrial fibrillation (AF) is a common heart rhythm disorder that increases the risk of stroke and other cardiovascular complications. The Watchman FLX device is a percutaneous device used for the closure of the left atrial appendage in patients with atrial fibrillation and prevents blood clots from forming, thereby decreasing the risk of stroke. However, device dislodgement during the procedure can occur and compromise the effectiveness of the device. In this case report, we present the experience of an 86-year-old man with a history of atrial fibrillation, coronary artery disease, hypertension, and recent gastrointestinal bleeding due to diverticulosis. During the procedure, the device became dislodged prior to the planned release from the shaft due to the difficult anatomy of the appendage, which caused the operator to over-torque and kink the delivery sheath. The kinked sheath prevented the transmission of torque to the appropriate region of the sheath and caused the device to unscrew prematurely. Fortunately, the device was self-deployed in a satisfactory position, and no further intervention was required. The patient did not experience any complications prior to discharge and follow-up echocardiography showed proper positioning of the device. This case highlights the importance of careful technique during the Watchman FLX procedure and the need to replace the delivery sheath if kinking is noted to prevent unintentional dislodgement of the device. In addition, the case was written with the aid of the artificial intelligence-powered language model ChatGPT and demonstrates its benefits as well as calls for caution while using it for medical writing.

Coronary Obstruction From TAVR in Native Aortic Stenosis: Development and Validation of Multivariate Prediction Model

BACKGROUND

Transcatheter aortic valve replacement (TAVR)-related coronary artery obstruction prediction remains unsatisfactory despite high mortality and novel preventive therapies.

OBJECTIVES

This study sought to develop a predictive model for TAVR-related coronary obstruction in native aortic stenosis.

METHODS

Preprocedure computed tomography and fluoroscopy images of patients in whom TAVR caused coronary artery obstruction were collected. Central laboratories made measurements, which were compared with unobstructed patients from a single-center database. A multivariate model was developed and validated against a 1:1 propensity-matched subselection of the unobstructed cohort.

RESULTS

Sixty patients with angiographically confirmed coronary obstruction and 1,381 without obstruction were included. In-hospital death was higher in the obstruction cohort (26.7% vs 0.7%; P < 0.001). Annular area and perimeter, coronary height, sinus width, and sinotubular junction height and width were all significantly smaller in the obstructed cohort. Obstruction was most common on the left side (78.3%) and at the level of the coronary artery ostium (92.1%). Coronary artery height and sinus width, but not annulus area, were significant risk factors for obstruction by logistic regression but performed poorly in predicting obstruction. The new multivariate model (coronary obstruction IF cusp height > coronary height, AND virtual valve-to-coronary distance ≤4 mm OR culprit leaflet calcium volume >600 mm3) performed well, with an area under the curve of 0.93 (sensitivity = 0.93, specificity = 0.84) for the left coronary artery and 0.94 (sensitivity = 0.92, specificity = 0.96) for the right.

CONCLUSIONS

A novel computed tomography-based multivariate prediction model that can be implemented routinely in real-world practice predicted coronary artery obstruction from TAVR in native aortic stenosis.

Long-term Outcomes of Transcatheter Aortic Valve Replacement With the Lotus Valve vs CoreValve/EvolutR: A Secondary Analysis of the REPRISE III Randomized Clinical Trial

IMPORTANCE

Long-term follow-up after transcatheter aortic valve replacement (TAVR) is of interest given that longitudinal data on mortality and durability of transcatheter heart valves are limited. The REPRISE III (Repositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus Valve System-Randomized Clinical Evaluation) randomized clinical trial compared the mechanically expanded Lotus valve with the self-expanding CoreValve/EvolutR TAVR platforms.

OBJECTIVE

To describe the final 5-year outcomes of the REPRISE III trial.

DESIGN, SETTING, AND PARTICIPANTS

This prespecified secondary analysis assessed the final 5-year clinical, functional, and echocardiographic outcomes of 912 patients from the REPRISE III trial, which was conducted at 55 centers in North America, Europe, and Australia between September 22, 2014, and December 24, 2015. Patients had high risk for aortic stenosis or severe or symptomatic aortic stenosis. Data were analyzed from September 22, 2014, to May 21, 2021.

INTERVENTION

Lotus valve or CoreValve/EvolutR TAVR platforms.

MAIN OUTCOMES AND MEASURES

Valve Academic Research Consortium-2 end points, hemodynamic measures, functional status, and health status were examined through the 5-year follow-up.

RESULTS

A total of 912 patients (mean [SD] age, 82.8 [7.3] years; 463 women [50.8%]) were randomized to either the Lotus valve group (n = 607) or CoreValve/EvolutR group (n = 305), with a baseline Society of Thoracic Surgeons risk score of 6.8%. Clinical follow-up data from the REPRISE III trial were available for 581 patients (95.7%) in the Lotus valve group and 285 patients (93.4%) in the CoreValve/EvolutR group. At 5 years, the cumulative event rate for all-cause mortality was 50.9% in the Lotus valve group vs 52.8% in the CoreValve/EvolutR group (P = .59). Disabling stroke was less frequent with the Lotus valve vs CoreValve/EvolutR (cumulative event rates, 8.3% vs 12.2%; P = .04), whereas the cumulative event rates for overall stroke were similar in both groups (14.1% vs 15.3%; P = .38). Insertion of a new permanent pacemaker (38.9% vs 27.3%; P < .001) and detection of prosthetic aortic valve thrombosis (5.8% vs 1.8%; P = .007) were more common in the Lotus valve group than in the CoreValve/EvolutR group. A smaller proportion of patients who received the Lotus valve experienced valve malpositioning (0% vs 2.6%; P < .001) and required the use of a second valve (1.0% vs 3.8%; P < .001) during the procedure compared with those who received the CoreValve/EvolutR. Compared with the Lotus valve group, the CoreValve/EvolutR group had a significantly lower mean (SD) aortic gradient (7.8 [4.2] mm Hg vs 12.6 [6.7] mm Hg; P < .001) and larger valve areas (1.57 [0.56] cm2 vs 1.42 [0.42] cm2; P = .10). After 5 years, the proportion of patients with moderate or greater paravalvular leak was not significantly higher with the CoreValve/EvolutR than with the Lotus valve (1.9% vs 0%; P = .31); however, the proportion of patients with mild paravalvular leak was higher in the CoreValve/EvolutR group compared with the Lotus valve group (23.1% vs 7.8%; P = .006). Long-term, similar improvements in New York Heart Association class and Kansas City Cardiomyopathy Questionnaire score were observed in both groups.

CONCLUSIONS AND RELEVANCE

The REPRISE III trial found that, at 5 years, the clinical outcomes of the Lotus valve were comparable to those of the CoreValve/EvolutR and that the Lotus valve was safe and effective.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02202434.

Abstract 42: Understanding Treatment Preferences For Patients With Tricuspid Regurgitation

Background: A quantitative patient preference study aims to understand tricuspid regurgitation (TR) patients’ priorities for symptom relief and treatment risk-benefit tradeoffs.

Methods: 150 clinically confirmed moderate or greater TR patients completed a discrete choice experiment survey online to elicit their preferences. Attributes (levels) tested were treatment (procedure, medical management), re-intervention risk (0%, 1%, 5%, 10%), medications in 2 yrs (none, reduce, same, more), shortness of breath (none/mild, moderate, severe) and swelling (never, 3x a week, daily). A mixed logit regression (MXL) model estimated preferences. MXL choice model calculated predicted probabilities.

Results: Shortness of breath contributed 66% to patients’ treatment decision making over other attributes. Patients’ predicted probability of preferring a procedure-like profile over a medical management-like profile was 99.7% and it was 78.9% for a medical management shortness of breath level change (Table 1). Subgroup analysis showed that patients over 64 yrs old preferred to more strongly avoid severe shortness of breath compared to under 65 (p<0.02), as did severe or worse TR patients over moderate. NYHA Class I/II patients more strongly preferred to avoid procedural re-intervention risk of 10% over Class III/IV (p<0.03).

Conclusion: TR patients prioritize improving shortness of breath and are willing to accept higher procedural re-intervention risk if it is alleviated, even to a small degree.

A discrepancy between CT angiography and transesophageal echocardiographic measurements of the annular size affect long-term survival following trans-catheter aortic valve replacement

Introduction: Accurate measurement of the aortic valve annulus is critical for proper valve sizing for the transcatheter aortic valve replacement (TAVR) procedure. While computed tomography angiography (CTA) is the widely-accepted standard, two-dimensional (2D) and three-dimensional(3D) transesophageal echocardiography (TEE) is commonly performed to measure the size of the aortic valve and to verify appropriate seating of prostheses.

Methods: Patients undergoing TAVR between 2013-2015 were examined. 2D- and 3D-TEEmeasurements were compared to CTA taken as standard. Patients were followed for at least one year. The presence and effect of discrepancy (defined as a difference of more than 10%) between CTA and TEE measurements on survival were examined.

Results: One hundred eighty-five patients (70 men) were included. 2D- and 3D-TEE measurements underestimated the annulus size by -1.49 and -1.32 mm, respectively. Discrepancies > 10% between TEE and CTA methods in estimating the aortic annulus size were associated with a decrease in post implant survival. The peak pressure gradient across the aortic prosthesis measured one year after the implant was higher in patients with an initial discrepancy between 3D-TEE and CTA measurements. In a multivariate cox-regression model, the discrepancy between CTA and 2D-TEE readings and the smaller size of the aortic annular area were the predictors of long-term survival.

Conclusion: Both 2D and 3D-TEE underestimate the aortic annulus measurements compared to CTA, with 2D-TEE being relatively more precise than 3D-TEE technology. The presence of a discrepancy between echocardiographic and CTA measurements of the aortic annulus is associated with a lower survival rate.

Complete flow control using transient concurrent rapid ventricular pacing or intravenous adenosine and afferent arterial balloon occlusion during transvenous embolization of cerebral arteriovenous malformations: case series

BACKGROUND

There are no reports that describe complete flow control using concurrent transient rapid ventricular pacing or intravenous (IV) adenosine and afferent arterial balloon flow arrest to aid transvenous embolization of cerebral arteriovenous malformations (AVM). We describe our experience with the use of this technique in patients undergoing transvenous AVM embolization.

METHODS

Consecutive patients in whom transvenous embolization was attempted at our institute between January 2017 and July 2019 were included. Anatomical AVM features, number of embolization stages, technique of concurrent transient rapid ventricular pacing and afferent arterial balloon flow arrest, complications, and clinical and radiological outcomes were recorded and tabulated.

RESULTS

Transvenous AVM embolization was attempted in 12 patients but abandoned in two patients for technical reasons. Complete embolization was achieved in 10 patients, five of whom had infratentorial AVMs. All 10 had a single primary draining vein. Rapid ventricular pacing was used in nine cases; IV adenosine injection was used in one case to achieve cardiac standstill. Complete AVM nidus obliteration was achieved with excellent neurologic outcome in nine cases, with transvenous embolization alone in two cases, and with staged transarterial followed by transvenous embolization in the others. Two patients developed hemorrhagic complications intraprocedurally. One patient was managed conservatively and the other operatively with AVM excision and hematoma evacuation; both made an excellent recovery without any neurologic deficits at 3 months.

CONCLUSION

Complete flow control using concurrent transient rapid ventricular pacing with afferent arterial balloon flow arrest technique is safe and feasible for transvenous embolization of select AVMs.

Two-Year Outcomes After Transcatheter Aortic Valve Replacement With Mechanical vs Self-expanding Valves: The REPRISE III Randomized Clinical Trial

Importance

To our knowledge, REPRISE III is the first large randomized comparison of 2 different transcatheter aortic valve replacement platforms: the mechanically expanded Lotus valve (Boston Scientific) and self-expanding CoreValve (Medtronic).

Objective

To evaluate outcomes of Lotus vs CoreValve after 2 years.

Design, Setting, and Participants

A total of 912 patients with high/extreme risk and severe, symptomatic aortic stenosis enrolled between September 22, 2014, and December 24, 2015, were randomized 2:1 to receive Lotus (607 [66.6%]) or CoreValve (305 [33.4%] at 55 centers in North America, Europe, and Australia. The first 2-year visit occurred on October 17, 2016, and the last was conducted on April 12, 2018. Clinical and echocardiographic assessments are complete through 2 years and will continue annually through 5 years.

Main Outcomes and Measures

All-cause mortality and all-cause mortality or disabling stroke at 2 years. Other clinical factors included overall stroke, disabling stroke, repeated procedures, rehospitalization, valve thrombosis, and pacemaker implantation. Echocardiographic analyses included effective orifice area, mean gradient, and paravalvular leaks (PVLs).

Results

Of 912 participants, the mean (SD) age was 82.8 (7.3) years, 465 (51%) were women, and the mean (SD) Society of Thoracic Surgeons predicted risk of mortality was 6.8% (4.0%). At 2 years, all-cause death was 21.3% with Lotus vs 22.5% with CoreValve (hazard ratio [HR], 0.94; 95% CI, 0.69-1.26; P = .67) and all-cause mortality or disabling stroke was 22.8% with Lotus and 27.0% with CoreValve (HR, 0.81; 95% CI, 0.61-1.07; P = .14). Overall stroke was 8.4% vs 11.4% (HR, 0.75; 95% CI, 0.48-1.17; P = .21); disabling stroke was more frequent with CoreValve vs Lotus (4.7% Lotus vs 8.6% CoreValve; HR, 0.53; 95% CI, 0.31-0.93; P = .02). More Lotus patients received a new permanent pacemaker (41.7% vs 26.1%; HR, 1.87; 95% CI, 1.41-2.49; P < .01) or had a valve thrombosis (3.0% vs 0.0%; P < .01) compared with CoreValve. More patients who received CoreValve experienced a repeated procedure (0.6% Lotus vs 2.9% CoreValve; HR, 0.19; 95% CI, 0.05-0.70; P < .01), valve migration (0.0% vs 0.7%; P = .05), or embolization (0.0% vs 2.0%; P < .01) than Lotus. Valve areas remained significantly larger and the mean gradient was lower with CoreValve than Lotus (valve area, mean [SD]: Lotus, 1.53 [0.49] cm2 vs CoreValve, 1.76 [0.51] cm2; P < .01; valve gradient, mean [SD]: Lotus, 13.0 [6.7] mm Hg vs 8.1 [3.7] mm Hg; P < .01). Moderate or greater PVL was more frequent with CoreValve (0.3% Lotus vs 3.8% CoreValve; P < .01) at 2 years. Larger improvements in New York Heart Association (NYHA) functional class were observed with Lotus compared with CoreValve (improved by ≥1 NYHA class: Lotus, 338 of 402 [84.1%] vs CoreValve, 143 of 189 [75.7%]; P = .01; improved by ≥2 NYHA classes: 122 of 402 [37.3%] vs 65 of 305 [21.3%]).

Conclusions and Relevance

After 2 years, all-cause mortality rates, mortality or disabling stroke were similar between Lotus and CoreValve. Disabling stroke, functional class, valve migration, and PVL favored the Lotus arm whereas valve hemodynamics, thrombosis, and new pacemaker implantation favored the CoreValve arm.

Trial Registration

clinicaltrials.gov Identifier: NCT02202434.

Pacemaker Implantation and Dependency After Transcatheter Aortic Valve Replacement in the REPRISE III Trial

Background

As transcatheter aortic valve replacement expands to younger and/or lower risk patients, the long‐term consequences of permanent pacemaker implantation are a concern. Pacemaker dependency and impact have not been methodically assessed in transcatheter aortic valve replacement trials. We report the incidence and predictors of pacemaker implantation and pacemaker dependency after transcatheter aortic valve replacement with the Lotus valve.

Methods and Results

A total of 912 patients with high/extreme surgical risk and symptomatic aortic stenosis were randomized 2:1 (Lotus:CoreValve) in REPRISE III (The Repositionable Percutaneous Replacement of Stenotic Aortic Valve through Implantation of Lotus Valve System—Randomized Clinical Evaluation) trial. Systematic assessment of pacemaker dependency was pre‐specified in the trial design. Pacemaker implantation within 30 days was more frequent with Lotus than CoreValve. By multivariable analysis, predictors of pacemaker implantation included baseline right bundle branch block and depth of implantation; diabetes mellitus was also a predictor with Lotus. No association between new pacemaker implantation and clinical outcomes was found. Pacemaker dependency was dynamic (30 days: 43%; 1 year: 50%) and not consistent for individual patients over time. Predictors of pacemaker dependency at 30 days included baseline right bundle branch block, female sex, and depth of implantation. No differences in mortality or stroke were found between patients who were pacemaker dependent or not at 30 days. Rehospitalization was higher in patients who were not pacemaker dependent versus patients without a pacemaker or those who were dependent.

Conclusions

Pacemaker implantation was not associated with adverse clinical outcomes. Most patients with a new pacemaker at 30 days were not dependent at 1 year. Mortality and stroke were similar between patients with or without pacemaker dependency and patients without a pacemaker.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier NCT02202434.

Effect of Mechanically Expanded vs Self-Expanding Transcatheter Aortic Valve Replacement on Mortality and Major Adverse Clinical Events in High-Risk Patients With Aortic Stenosis: The REPRISE III Randomized Clinical Trial

IMPORTANCE

Transcatheter aortic valve replacement (TAVR) is established for selected patients with severe aortic stenosis. However, limitations such as suboptimal deployment, conduction disturbances, and paravalvular leak occur.

OBJECTIVE

To evaluate if a mechanically expanded valve (MEV) is noninferior to an approved self-expanding valve (SEV) in high-risk patients with aortic stenosis undergoing TAVR.

DESIGN, SETTING, AND PARTICIPANTS

The REPRISE III trial was conducted in 912 patients with high or extreme risk and severe, symptomatic aortic stenosis at 55 centers in North America, Europe, and Australia between September 22, 2014, and December 24, 2015, with final follow-up on March 8, 2017.

INTERVENTIONS

Participants were randomized in a 2:1 ratio to receive either an MEV (n = 607) or an SEV (n = 305).

MAIN OUTCOMES AND MEASURES

The primary safety end point was the 30-day composite of all-cause mortality, stroke, life-threatening or major bleeding, stage 2/3 acute kidney injury, and major vascular complications tested for noninferiority (margin, 10.5%). The primary effectiveness end point was the 1-year composite of all-cause mortality, disabling stroke, and moderate or greater paravalvular leak tested for noninferiority (margin, 9.5%). If noninferiority criteria were met, the secondary end point of 1-year moderate or greater paravalvular leak was tested for superiority in the full analysis data set.

RESULTS

Among 912 randomized patients (mean age, 82.8 [SD, 7.3] years; 463 [51%] women; predicted risk of mortality, 6.8%), 874 (96%) were evaluable at 1 year. The primary safety composite end point at 30 days occurred in 20.3% of MEV patients and 17.2% of SEV patients (difference, 3.1%; Farrington-Manning 97.5% CI, -∞ to 8.3%; P = .003 for noninferiority). At 1 year, the primary effectiveness composite end point occurred in 15.4% with the MEV and 25.5% with the SEV (difference, -10.1%; Farrington-Manning 97.5% CI, -∞ to -4.4%; P<.001 for noninferiority). The 1-year rates of moderate or severe paravalvular leak were 0.9% for the MEV and 6.8% for the SEV (difference, -6.1%; 95% CI, -9.6% to -2.6%; P < .001). The superiority analysis for primary effectiveness was statistically significant (difference, -10.2%; 95% CI, -16.3% to -4.0%; P < .001). The MEV had higher rates of new pacemaker implants (35.5% vs 19.6%; P < .001) and valve thrombosis (1.5% vs 0%) but lower rates of repeat procedures (0.2% vs 2.0%), valve-in-valve deployments (0% vs 3.7%), and valve malpositioning (0% vs 2.7%).

CONCLUSIONS AND RELEVANCE

Among high-risk patients with aortic stenosis, use of the MEV compared with the SEV did not result in inferior outcomes for the primary safety end point or the primary effectiveness end point. These findings suggest that the MEV may be a useful addition for TAVR in high-risk patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02202434.

Regulation of Streptococcus mutans PTS Bio by the transcriptional repressor NigR

Streptococcus mutans is implicated in human dental caries, and the carbohydrate metabolism of this organism plays an important role in the formation of this disease. Carbohydrate transport and metabolism are essential for the survival of S. mutans in the oral cavity. It is known that a unique phosphoenolpyruvate-sugar phosphotransferase system PTS(B) (io) of S. mutans UA159 is expressed in sucrose-grown biofilms (Mol Oral Microbiol 28: 2013; 114). In this study we analyzed the transcriptional regulation of the operon (O(B) (io) ) encoding the PTS(B) (io) and showed that it was repressed by NigR, a LacI-like transcriptional regulator. Using electro-mobility shift assay, we described two operators to which NigR bound with different affinities. We also identified the transcriptional start site and showed that one of the operators overlaps with the promoter and presumably represses initiation of transcription. Mutational analyses revealed the key nucleotides in the operators required for high-affinity binding of NigR. PTS(B) (io) is expressed in S. mutans biofilms so understanding its regulation may provide improved strategies for caries treatment and prevention.

A Pilot Cross-Over Study to Evaluate Human Oral Bioavailability of BCM-95CG (Biocurcumax), A Novel Bioenhanced Preparation of Curcumin

Curcumin, the bioactive component of turmeric, Curcuma longa has an exceptionally wide spectrum of activities including antioxidant, anti-inflammatory and anti-cancer properties, and is currently under different phases of clinical trials for various types of soft tissue cancers. However, although in vitro and animal studies have shown anticancer activities of curcumin for virtually all types of human cancers, its poor bioavailability in the human body has severely limited its application to these diseases. Methods to increase its oral bioavailability are a subject of intense current research. Reconstituting curcumin with the non-curcuminoid components of turmeric has been found to increase the bioavailability substantially. In the present clinical study to determine the bioavailability of curcuminoids, a patented formulation, BCM-95^®CG was tested on human volunteer group. Normal curcumin was used in the control group. Curcumin content in blood was estimated at periodical intervals. After a washout period of two weeks the control group and drug group were crossed over BCM-95^®CG and curcumin, respectively. It was also compared with a combination of curcumin-lecithin-piperine which was earlier shown to provide enhanced bioavailability. The results of the study indicate that the relative bioavailability of BCM-95^®CG (Biocurcumax™) was about 6.93-fold compared to normal curcumin and about 6.3-fold compared to curcumin-lecithin-piperine formula. BCM-95^®CG thus, has potential for widespread application for various chronic diseases.

Assessment of a nuclear affinity labeling method for tracking implanted mesenchymal stem cells

Therapeutic implantation of mesenchymal stem cells (MSCs) is entering the realm of clinical trials for several human diseases, and yet much remains uncertain regarding their dynamic distribution and cell fate after in vivo application. Discrepancies in the literature can be attributed in part to the use of different cell labeling/tracking methods and cell administration protocols. To identify a stem cell detection method suitable for myocardial implantation in a large animal model, we experimented on three different MSC labeling methods: adenovirus-mediated expression of enhanced green fluorescence protein (EGFP) and beta-galactosidase (LacZ), and nuclear staining with DAPI. Intramuscular and intracoronary administrations of labeled porcine MSCs identified the nuclear affinity dye to be a reliable stem cell tracking marker. Stem cell identification is facilitated by an optimized live cell labeling condition generating bright blue fluorescence sharply confined to the nucleus. DAPI-labeled MSCs retained full viability, ceased proliferation, and exhibited an increased differentiation potential. The labeled MSCs remained fully active in expressing key growth factor and cytokine genes, and notably exhibited enhanced expression of the chemokine receptor CXCR4 and its ligand SDF1, indicating their competency in response to tissue injury. Histological analysis revealed that approximately half a million MSCs or approximately 2% of the administered MSCs remained localized in the normal pig heart 2 weeks after coronary infusion. That the vast majority of these identified MSCs were interstitial indicated the ability of MSCs to migrate across the coronary endothelium. No evidence was obtained indicating MSC differentiation to cardiomyocyte.

Regional Desensitization of β-Adrenergic Receptor Signaling in Swine With Chronic Hibernating Myocardium

Contractile reserve during submaximal beta-adrenergic stimulation is attenuated in patients and swine with hibernating myocardium. We tested the hypothesis that this arises as a regional adaptive response in beta-adrenergic adenylyl cyclase coupling. Pigs (n=8) were studied 3 months after instrumentation with a left anterior descending artery (LAD) stenosis when flow (LAD, 0.7+/-0.2 versus 1.2+/-0.1 mL/min per gram in normal remote; P<0.05) and wall thickening (LAD, 15.5 [corrected]+/-3.2% versus 40.0+/-5.5% in remote; P<0.05) were reduced in the absence of infarction. Whereas basal cAMP production was normal (LAD, 87+/-18 versus 91+/-19 pmol/mg per minute; P=NS), responses to isoproterenol were blunted (LAD, 83+/-6 versus 146+/-25 pmol/mg per minute in remote; P<0.05). beta-receptor density and subtype were unchanged, but there was a reduction in the number of high-affinity binding sites (LAD, 40+/-4% versus 53+/-7% in normal remote; P<0.05). The Gialpha2/Gsalpha ratio increased (LAD, 1.8+/-0.3 versus 0.99+/-0.3 in remote myocardium; P<0.05), although GppNHp-stimulated cAMP production was equivocally reduced. Forskolin responses were unchanged and similar to shams. These data indicate regional attenuation of beta-receptor adenylyl cyclase signaling in hibernating myocardium. This blunts the local contractile response to beta-adrenergic stimulation and may serve to protect against a myocardial supply/demand imbalance when external determinants of myocardial workload increase during sympathetic activation.

Long-term outcome of rubber band ligation for symptomatic primary and recurrent internal hemorrhoids

PURPOSE

Rubber band ligation therapy for symptomatic hemorrhoidal disease has been used for many years and is a well-accepted treatment modality, but information on long-term outcome is limited. Our goals were to determine safety and long-term efficacy of this treatment.

METHODS

A retrospective chart review of patients undergoing rubber band ligatures for symptomatic internal hemorrhoids in a single practice was conducted. Information on presenting symptoms, number of bands applied, response to therapy, complications encountered, length of follow-up, interval to recurrent symptoms when applicable, and subsequent therapy were documented. Supplemental information was obtained from telephone follow-up. Outcome was categorized as success or failure, in which success was defined as: permanent relief of symptoms for follow-up period; marked improvement in symptomatology with rare manifestation of bleeding (< or = 1/month); symptom relief for a limited period of time (> or = 100 days), and failure was defined as: modest improvement (decreased but not relief of symptoms); or no improvement in symptoms.

RESULTS

A total of 805 patients underwent 2,114 rubber band ligatures. Most common presenting symptoms were bleeding in 731 patients (90.8 percent) and prolapsing in 382 patients (47.5 percent). The median number of bands placed was two (range, 1-17). The median time between bandings was 4.7 (range, 1.1-35.6) weeks. Median follow-up time was 1,204 (range, 14-9,571) days. Excluding 104 patients lost to follow-up (never returned after initial treatment), success was obtained in 70.5 percent (494/701) and failure in 29.5 percent (207/701) of patients. Success rates were similar for all degrees of hemorrhoids. Hemorrhoidal disease requiring the placement of four or more bands was associated with a trend in higher failure rates and greater need for subsequent hemorrhoidectomy. Complications per treatment series included bleeding (2.8 percent), thrombosed external hemorrhoids (1.5 percent), and bacteremia (0.09 percent). Higher bleeding rates were encountered with the use of acetylsalicylic acid/nonsteroidal anti-inflammatory drugs and warfarin. Time to recurrence was less with subsequent treatment courses. Treatment of recurrent symptoms with rubber band ligation resulted in success rates of 73.6, 61.4, and 65 percent for first, second, and third recurrences respectively. This resulted in a cumulative success rate of 80.2 percent for this method of treatment.

CONCLUSIONS

Rubber band ligatures are safe and effective therapy for symptomatic internal hemorrhoids. It can be used to treat all degrees of hemorrhoids with similar effectiveness. The likelihood of success is lower if more than four bands are needed to eliminate symptoms. The use of acetylsalicylic acid/nonsteroidal anti-inflammatory drugs and warfarin is associated with higher bleeding rates. Rubber band ligatures for recurrence of symptoms is effective; however, time to recurrence is less with subsequent treatments.

Factors influencing mortality and myocardial infarction after coronary artery bypass grafting

Although the mortality for coronary artery bypass graft surgery has declined, some categories of patients are still recognized as being at greater risk. Because the mortality, even for most patients with risk factors, is less than 10%, evaluating this risk and any improvement arising from changing techniques requires thousands of cases. The need for these large patient numbers makes the evaluation of changes difficult. Even when other risk factors are accounted for in the mortality estimate, the patient's age remains an important factor, although there is no obvious reason why this should be so. Similarly, female sex is well recognized as a risk factor. However, the tendency for women to have a smaller body surface area and corresponding smaller arterial diameters may be the explanation. Perfusion time appears to have a strong influence on mortality after it exceeds about 90 minutes, and a similar influence on myocardial infarction also appears to be present. The increased risk of myocardial infarction with unstable angina may relate to disruption of the normal endothelial vasodilatation caused by nitric oxide.

Mortality and myocardial infarction after coronary artery surgery. A review of 12,003 patients

OBJECTIVE

To review the results of uncomplicated coronary artery bypass graft surgery and to identify factors which influence operative mortality (OM) and postoperative myocardial infarction (PMI).

DESIGN

An analysis of the outcome in patients having coronary artery bypass graft surgery for the first time from 1978 to 1990 inclusive.

SETTING

The Cardiothoracic Surgery Unit at the Royal Adelaide Hospital.

PARTICIPANTS

Twelve thousand and twenty-two patients had coronary artery bypass graft surgery only. Complete data were available for 12,003 patients.

RESULTS

There was an overall mortality rate of 0.99% and a postoperative myocardial infarction rate of 1.34%. Older patients and women had a higher operative mortality rate. Both unstable angina and poor ventricular function increased the mortality rate. The only significant operative factor was the perfusion time. There was a more than 16-fold increase in mortality in patients who had an average bypass time (48 minutes) compared with those whose bypass time was 100 minutes or more (0.63% v. 10.3%). The PMI rate changed over the study period, and was also influenced by the presence of unstable angina and the duration of bypass: unstable angina doubled the rate from 0.86% to 1.91%, and with an average bypass time the PMI rate was 0.56% whereas with a bypass time of 100 minutes or more the rate increased to 7.7%.

CONCLUSIONS

The outcome after coronary artery bypass graft surgery is strongly dependent on the perfusion time and the presence of unstable angina. Older patients and women are more likely to die during the operation.

Nifedipine for postoperative blood pressure control following coronary artery vein grafts

The drug control of raised blood pressure following coronary artery bypass grafting was studied in 20 patients during the early postoperative period. On a random basis, 10 patients were given intranasal nifedipine and 10 other patients received intranasal saline. If the systolic pressure was raised, it was treated by an infusion of sodium nitroprusside. The systolic pressure abated in those treated with nifedipine so that 7 of the 10 did not require any other treatment in the first hour. The reduction in pressure was accomplished without an increase in heart rate. The requirement for sodium nitroprusside to control the pressure was much less in the first hour postoperatively in the nifedipine treated group and at 4 hours, the effect of nifedipine was still apparent. This study demonstrates that intranasal nifedipine is an effective adjunct for controlling raised blood pressure in the early postoperative period.

Fresh autologous blood transfusion and platelet counts after cardiopulmonary bypass surgery

The effect of fresh autologous blood transfusion on platelet count and blood requirement in the early postoperative period is examined in a control group and in patients receiving early and late autologous replacement. Withdrawal of blood in the autologous groups appeared to enhance platelet numbers as the autologous groups had higher mean platelet counts than the control group immediately after bypass, in spite of having lower mean haematocrit. After bypass all groups showed a progressive rise in platelet count with time. A substantial part of the rise was explained by haemoconcentration resulting from fluid shifts but there was also an increase in the total circulating platelet numbers. There was no difference in postoperative blood loss between the three groups. Autologous blood replacement hastens the postoperative rise in platelet count but does not alter the postoperative blood loss.