Right Atrial Collision Time (RACT): a novel marker of propensity for typical atrial flutter

Background

The risk of typical atrial flutter (AFL) is increased by factors that increase right atrial (RA) size or cause scarring to reduce conduction velocity. These characteristics ensure the macro re-entrant wave front does not meet its refractory tail. The time taken to traverse the circuit would take account of both of these characteristics (being equal to distance divided by velocity), and may provide a superior marker of propensity to develop AFL.

Purpose

To investigate right atrial collision time (RACT) as a marker of typical AFL.

Methods

This single centre, prospective study recruited consecutive typical AFL ablation cases that were in sinus rhythm. Controls were consecutive cases other than atrial fibrillation and >50 years of age. Exclusion criteria for both groups were a prior ablation in the RA and class I and III antiarrhythmics. While pacing the coronary sinus ostium at 600 ms, a local activation time map was created to locate the latest collision point on the anterolateral wall, excluding the RA appendage (Figure 1). This RACT approximates half a revolution.

Results

The AFL group's (n=34) mean RACT was 132.5±15.06 vs 98.7±12.23ms in the controls (n=40) (p<0.01). No significant difference was observed for age (mean 65.6 vs 62.6 (p=0.18)), male (68.8% vs 60% (p=0.59)), body surface area (mean 2.1 vs 2.03 m2 (p=0.24)). The RACT also proved to be a superior marker than the echocardiographic measurement of right atrial area in an apical four chamber view (mean 17.8 vs 16.3 cm2 (p=0.21).A ROC curve indicated an AUC of 0.97 (95% CI: 0.93–1.0, p<0.01). A RACT cut-off of 120 ms had a specificity of 99% and a sensitivity of 75%.

Conclusion

RACT is a novel and promising marker of propensity for typical AFL. The ability to predict AFL would be of significant clinical value given the risk of stroke and frequent need for ablation.

Funding Acknowledgement

Type of funding source: None

1681 Carotid screening prior to stress echocardiography, an opportunity to assess cardiovascular risk?

BACKGROUND

Screening for atherosclerosis is an important method for assessing cardiovascular (CV) risk. Our data with carotid imaging shows a normal a carotid is associated with a very low 10-year CV risk of 1.6%. Even a low risk carotid still predicts a favourable outcome, 5.6-7.0% CV risk over 10 years. Increasing plaque burden as assessed by either total plaque area (>25mm2) or plaque score (>1) is associated with increasing CV risk, ranging from 20% to >30% over 10 years.

PURPOSE

This analysis was performed to estimate the prevalence and severity of carotid disease in men and women presenting for stress ECHO, with no prior documented evidence of CV disease.

METHODS

Data was collected from October 3, 2011 to January 22, 2019. Male patients aged 40-70yrs and female patients aged 50-75yrs undergoing stress ECHO underwent a screening carotid examination prior to the test. This involves only 2-3 images on each side to include, the CCA, carotid bulb and ICA. Maximal CCA IMT is measured using an automatic edge detection method, plaque score is calculated using the Rotterdam method and plaque area is measured in the carotid bulb and ICA bilaterally. Total plaque area being the sum of all area measurements. Apart from age criteria, patients were also excluded if they were diabetic, already taking a statin, or had a previous history of any vascular disease. A low-risk carotid was defined as a maximal CCA IMT <1.00m,with a plaque score of "0" or "1" providing the total plaque area was <25mm2. An unpaired t-test was used to detect differences between means and the Fisher’s exact test was used to detect differences between proportions. A p value of <0.05 was considered statistically significant.

RESULTS

There were 1683 patients, 1175 females and 508 males with a mean age of 60.9 ± 7.4 years. Of the 1683 patients 1058 had evidence of carotid plaque (62.9%), 368 males (72.4%) and 690 females (58.7%). 726 patients were classified as low-risk and 957 patients were classified as high-risk. See Table 1.

CONCLUSIONS

A brief screening carotid examination prior to stress ECHO reveals a large percentage of both men and women who have evidence of atherosclerosis, of which 56.9% are high-risk. These patients could be identified while in the ECHO laboratory. The patients could then be offered guideline therapy with statin therapy and low dose ASA.

Table 1. Number Age CCA IMT PS 0-1 PS 2-3 PS 4-6 Low-risk High-risk Males 508 58.4 ± 7.8 1.14 ± 0.47 138 213 56 161 347 Females 1175 62.0 ± 7.0 0.99 ± 0.49 726 395 54 565 610 P value <0.0001 <0.0001 <0.0001 <0.005 <0.0001 <0.0001 <0.0001 PS = Plaque score.

P4402Effect of carnitine supplementation on progression of carotid plaque in the metabolic syndrome: the ECoM study

Background/Introduction

L-carnitine (L-C) has been investigated as a potential therapy for cardiovascular (CV) disease, but its direct effects on human atherosclerosis are unknown. Epidemiological studies suggest a possible reduction of CV risk factors following treatment, whereas animal studies have shown that L-C may increase pro-atherogenic metabolites.

Purpose

The purpose of this study was to determine whether L-C therapy led to atherosclerosis progression or regression by direct quantification of carotid atherosclerotic lesions in patients with metabolic syndrome (MetS).

Methods

This study was a Phase 2, prospective, parallel, double blinded, randomized, placebo-controlled, two-center trial. MetS was defined according to the International Diabetes Federation harmonized definition, where presence of any 3 of the 5 following risk factors constituted a diagnosis: elevated waist circumference; elevated triglycerides; reduced HDL or treated; elevated blood pressure or treated; elevated glucose or HbA1c or treated. Participants with a baseline carotid total plaque volume (TPV) ≥50 mm3 were randomized to placebo or 2 g L-C daily for 6 months. Plaque progression was quantified by 3D carotid ultrasound for change in TPV and reduction in vessel lumen area (% area stenosis, Fig. 1). Absolute differences were assessed on the raw scale, while percent change on the log scale. Analysis of covariance (ANCOVA) was used to assess within- and between-arm differences.

Results

Of the 177 participants randomized, 157 completed the study (L-C n=76, placebo n=81). No statistically significant difference between arms was found in the primary outcome (TPV). However, there was progression of plaque stenosis in the treatment arm: the L-C group had an increase in stenosis of 9.8% (p=0.01) higher than the placebo arm, and a 2.7% (p=0.03) greater absolute change. Total cholesterol and LDL levels (0.10 mmol/L and 0.05 mmol/L, respectively) were higher in the intervention arm compared to the placebo arm (−0.06 mmol/L and −0.07 mmol/L).

Figure 1

Conclusions

We observed progression of atherosclerosis with L-C therapy compared to placebo in patients with MetS. The clear lack of benefit of L-C therapy in this population raises serious concerns for its further use as a potential therapy. Given its association with pro-atherogenic metabolites our study offers further understanding of the atherosclerotic process.

Acknowledgement/Funding

Heart and Stroke Foundation of Canada

3042Gender differences in the prevalence of a normal IMT with increasing severity of carotid disease

Background

The ARIC group has shown that increasing IMT is only predictive of increased cardiovascular (CV) risk in males (M). Plaque is predictive of increased CV risk in both M and females (F).

Purpose

To determine the prevalence of a normal IMT (<1.00mm) in M and F with evidence of carotid plaque. Plaque score (PS) was used as a measure of severity of disease.

Methods

Our database was searched for patients with all the required data, IMT, PS and plaque area. IMT was measured with automatic edge detection software, PS was calculated using the Rotterdam method and plaque area was measured in the carotid bulb and ICA bilaterally. Only the first carotid study was used in the analysis. PS of 0–6 were used to estimate plaque severity. ANOVA and the Fisher's exact test were used to detect differences between groups. A p value of <0.05 was considered significant.

Results

There were 5981 patients, 3062 M and 2919 F with an average age of 62.1±11.3 years. Table I. indicates that with increasing PS, age, IMT and plaque area all increase, with a reciprocal decrease in the proportion of patients with a normal IMT. Of 3829 patients with carotid plaque 1355 (35.4%) had an IMT <1.00mm. There were clear gender differences with a much higher prevalence of a normal IMT in F with carotid plaque than M, 776 of 1772 (43.8%) versus 579 of 2057 (28.1%), p<0.0001, Fisher's exact test. This gender difference applies to most groups with increasing plaque burden except those with the most severe disease (PS “5–6”).

Table 1 PS “0” PS “1” PS “2” PS “3” PS “4” PS “5–6” N 2152 896 1209 792 562 370 ANOVA Age 57.6±12.2 60.4±9.2 63.0±9.5 66.5±9.3 67.8±8.9 71.5±8.8 <0.0001 IMT 0.94±0.32 1.00±0.23 1.08±0.29 1.30±0.55 1.51±0.75 2.77±0.88 <0.0001 Plaque area 0 16.5±11.6 35.1±20.0 58.6±29.9 91.0±43.1 130.4±61.3 <0.0001 Males 1005 424 627 422 331 253 IMT <1.00mm 671 222 226 77 50 4 Percentage 66.8% 52.4% 36.0% 18.2% 15.1% 1.6% Females 1147 472 582 370 231 117 IMT <1.00mm 879 293 288 136 57 2 Percentage 76.6% 62.1% 49.5% 36.8% 24.6% 1.7% Fisher's test <0.0001 <0.005 <0.0001 <0.0001 <0.0001 NS PS = Carotid ÷ 6 segments, assigned “0” or “1” if plaque is absent or present.

Conclusions

Significantly more women with carotid plaque have a normal IMT. This may explain why IMT fails to be predictive of CV risk in women.

Activity of patupilone for the treatment of recurrent or progressive brain metastases in patients (pts) with non-small cell lung cancer (NSCLC): An open-label, multicenter, phase II study

18058

Background: Advances in systemic chemotherapy have improved overall survival for patients with advanced NSCLC; unfortunately, CNS metastasis is common and limits survival benefits with current therapies. Unlike taxanes, preclinical findings suggest that the novel epothilone, patupilone, crosses the blood-brain barrier in 3 animal species and also has antitumor effects in brain tumor models. Results of an ongoing phase I/II study of patupilone as second-line therapy in pts with NSCLC are encouraging. The present study is evaluating the efficacy of patupilone in pts with brain metastases from NSCLC who have failed or recurred after previous chemotherapy, surgery, and/or radiation to the brain. Methods: This open-label, single-arm, multicenter, phase II study has a 2-stage design (25 pts per stage). Eligible pts have histologically confirmed NSCLC and = 1 recurrent, bidimensionally measurable intracranial lesion = 2 cm. Patupilone was administered IV at 10 mg/m2 as a single 20-min IV infusion every 3 weeks until disease progression, satisfactory response, or unacceptable toxicity. The primary multinomial endpoint was a combination of early progression (disease progression or death before cycle 1, day 21) and response rate (alive without progression at cycle 4, day 1). Results: An interim analysis of 13 pts with a median age of 62 years (range, 40–67 years) is reported. The most common adverse events (AEs) related to study drug were NCI CTC grade 1/2 diarrhea in 7 (54%) pts, nausea in 3 (23%), and fatigue in 2 (15%). Only 2 serious AEs (grade 4 colitis and grade 3 diarrhea) and 2 additional grade 3 AEs (diarrhea, neutropenia) were reported in 1 pt each. Three (23%) pts experienced early disease progression. Five (38%) pts responded, receiving a median 10 cycles (range, 5 to 12 cycles) and were alive without progression on cycle 4, day 1. Conclusions: Patupilone has activity in patients with CNS metastases from advanced NSCLC and is well tolerated. Additional investigation of patupilone as a treatment for brain metastases from NSCLC is warranted.

[Table: see text]

Worthing nipple discharge aspirator

Assessment of patients with nipple discharge traditionally involves using a custom made device or by massaging or squeezing the nipple-areola complex to elicit the discharge. This can be painful and embarrassing for the patient. We describe a nipple discharge aspirator that is effective, cheap, easily available, acceptable to the patient and avoids squeeze technique.

Efficacy of patupilone in advanced local or metastatic gastric cancer: A phase IIa trial

4069

Background: Although the use of taxanes has produced encouraging response rates in patients with advanced local or metastatic gastric cancer, outcomes remain unsatisfactory. Patupilone (EPO906; epothilone B), a novel microtubule stabilizer, has demonstrated anti-tumor activity against a broad range of tumors in vitro and in animal models. The present trial evaluated the efficacy of patupilone in patients with locally advanced or metastatic gastric cancer. Methods: Patients with confirmed gastric adenocarcinoma (defined by RECIST) received patupilone 2.5 mg/m2/wk by single 5- to 7-minute IV infusion for 3 weeks, followed by 1 week off (4-week cycle). Additional inclusion criteria: WHO performance status ≤2, age ≥18 years, life expectancy ≥3 months, and no major hematologic, renal, or hepatic impairment. The primary objective of this open-label, single-arm, 2-stage, multicenter study was to determine the objective response rate (using RECIST) of treatment with patupilone in this population. Results: All 22 patients enrolled were evaluable. Mean age was 61.1 years, 63.6% were men, and 72.7% were oriental. Of 18 patients (81.8%) who completed the study, 10 (45.5%) had disease progression and 8 (36.4%) died from the disease; of 4 discontinuations, 3 were due to adverse events (AEs) and 1 to abnormal alkaline phosphatase. Overall response: 2 patients had partial responses, 6 disease stabilization, 12 disease progression, and 2 unknown. The duration of response in the 2 partial responders was 176 and 113+ days, with the latter censored at 113 days. The most frequently reported AEs were diarrhea (n = 18), nausea (n = 14), vomiting (n = 13), abdominal pain (n = 10), and fatigue (n = 10). Of these AEs, 9 were grade 3 (4 diarrhea, 3 vomiting, 1 nausea, and 1 fatigue) and 2 were grade 4 (1 nausea and 1 vomiting). Grade 4 AEs also included 1 gastric outlet obstruction and 1 dehydration. Conclusions: Patupilone resulted in an overall tumor response/disease stabilization rate of 36.4%, was well tolerated, and may prove to be a viable alternative to taxane treatment in advanced local/metastatic gastric cancer.

[Table: see text]

Efficacy and safety of patupilone in non-small cell lung cancer (NSCLC): A phase I/II trial

7104

Background: Based on its activity in a wide range of tumors including those that are taxane resistant, the novel microtubule stabilizer patupilone (EPO906; epothilone B) has the potential to treat NSCLC. Fifty patients were enrolled in phase I to evaluate safety, efficacy, and optimal dose. The phase II part of this study is investigating the antitumor activity of patupilone in 53 patients with stage IIIB/IV NSCLC. Methods: Patients with histologically or cytologically confirmed unresectable, locally advanced, or metastatic NSCLC documented before 1st-line therapy without symptomatic or uncontrolled brain metastases received patupilone at a starting dose of 10.0 mg/m2 q3wk by 20-minute IV infusion. Additional inclusion criteria: age ≥18 years; WHO performance status 0–1; prior treatment with a platinum-containing regimen. Primary objective of the phase II, single-arm, 2-stage, multicenter trial: to determine activity of patupilone q3wk (overall response using modified RECIST) in NSCLC. An additional cohort with recurrent brain metastases from NSCLC is being accrued to evaluate safety, pharmacokinetics, and activity. Results: In phase I, all patients received prior treatment with platinum therapy; 28% had received taxanes and 78% nontaxanes. Patupilone dose was escalated from 6.5 to 13.0 mg/m2 q3wk. Dose-limiting toxicities occurred in 4 patients: 1 with grade 3 asthenia and 3 with grade 3 diarrhea at various dose levels. The most frequent adverse events (AEs) were diarrhea (66%), nausea (40%), vomiting (34%), paraesthesia (32%), abdominal pain (30%), and fatigue (30%). The most frequent grade 3 AE was diarrhea (14%); a grade 4 AE (asthenia) occurred in 1 patient. Overall phase I response: 5 PR, 16 SD, and 26 PD. Based on risk-benefit analyses, 10.0 mg/m2 q3wk was recommended as the phase II dose. Phase II is ongoing: 25 of 53 patients (15 men and 6 women with NSCLC; 2 men and 2 women with brain metastases) have been enrolled. Conclusions: In phase I, patupilone q3wk was safe and well tolerated, with antitumor activity in patients with advanced pretreated NSCLC. Data from phase II will be available at time of presentation.

[Table: see text]

Patupilone in chemotherapy-pretreated patients with advanced colorectal cancer (CRC) receiving nutritional support and intensive diarrhea management: A phase I multicenter trial

3593

Background: In previous clinical studies, a positive effect was noted in patients with CRC heavily pretreated with chemotherapy who received the novel microtubule stabilizer patupilone (EPO906; epothilone B) once-weekly or q3wk; however, susceptibility to diarrhea was high and response rates were modest. This dose-escalation trial examined the safety/efficacy of 3 patupilone regimens in chemotherapy-pretreated patients with CRC who received nutritional support and intensive diarrhea management. Methods: Patients with histologically confirmed CRC, without ileo- or colostomy or history of abdominal/pelvic irradiation, and who relapsed or were refractory after ≤4 prior chemotherapy regimens received nutritional support, intensive diarrhea management if needed, and patupilone as IV bolus q3wk or 1-or 5-day continuous IV (CIV) q3wk at doses of 6–10 mg/m2. Additional inclusion criteria: ≥1 measurable lesion; age ≥18 years; WHO performance status <2; no hepatic, renal, or hematologic impairment. Nutritional supplementation: ω-3 fatty acids, pre- and probiotics, antisecretory factor, and glutamine. Diarrhea management: appropriate clinical care, loperamide, opium tincture, codeine, and octreotide. Dose escalation was per protocol following a 3+3 design. The primary objective of this trial was to determine the maximum tolerated dose of the 3 patupilone treatment schedules in these patients. Results: Forty-four patients were enrolled: bolus, n = 22; 5-day CIV, n = 3; 1-day CIV, n = 19. Mean age 58.8 years; 95% Caucasian; 54% men. In the 5-day CIV arm, enrollment was closed at the 6.5-mg/m2 dose level since 2 dose-limiting toxicities (severe diarrhea) were reported. With bolus and 1-day CIV, the current doses are 10 and 9 mg/m2, respectively. The most common adverse events in the 43 patients evaluable for safety were diarrhea (70%), asthenia (23%), and nausea (21%). Grade 3 diarrhea occurred in 9 patients (21%). Overall response: 4 partial responses and 13 stable disease. Conclusions: Preliminary results suggest that patupilone monotherapy administered q3wk + intensive diarrhea management may prove beneficial in patients with CRC who progressed after 2–3 chemotherapy regimens.

[Table: see text]

Effect of lindane on hepatic and brain cytochrome P450s and influence of P450 modulation in lindane induced neurotoxicity

Oral administration of lindane (2.5, 5, 10 and 15 mg/kg, body weight) for 5 days was found to produce a dose-dependent increase in the activity of P450 dependent 7-ethoxyresorufin-O-deethylase (EROD), 7-pentoxyresorufin-O-dealkylase (PROD) and N-nitrosodimethylamine demethylase (NDMA-d) in rat brain and liver. A significant increase in the hepatic and brain P450 monooxygenases was also observed when the duration of exposure of low dose (2.5 mg/kg) of lindane was increased from 5 days to 15 or 21 days. As observed with different doses, the magnitude of induction in the activity of P450 monooxygenases was several fold higher in liver microsomes when compared with the brain. Western blotting studies have indicated that the increase in the P450 enzymes could be due to the increase in the expression of P450 1A1/1A2, 2B1/2B2 and 2E1 isoenzymes. In vitro studies using organic inhibitors specific for individual P450 isoenzymes and antibody inhibition experiments have further demonstrated that the increase in the activity of PROD, EROD and NDMA-d are due to the increase in the levels of P450 2B1/2B2, 1A1/1A2 and 2E1 isoenzymes, respectively. Induction studies have further shown that while pretreatment of 3-methylcholanthrene (MC), an inducer of P4501A1/1A2, did not produce any significant effect in the incidence of lindane induced convulsions, pretreatment with phenobarbital (PB), an inducer of P450 2B1/2B2 or ethanol, an inducer of P450 2E1 catalysed reactions, significantly increased the incidence of lindane induced convulsions. Similarly, when the P450-mediated metabolism of lindane was blocked by cobalt chloride incidence of convulsions was increased in animals treated with lindane indicating that lindane per se or its metabolites formed by PB or ethanol inducible P450 isoenzymes are involved in its neurobehavioral toxicity.

Open lung biopsy in diffuse infiltrative lung disease with progressive dyspnoea: is it useful?

Eleven subjects, aged between 15 and 60 years, presenting with diffuse infiltrative lung disease (DILD) and progressive dyspnoea, underwent an open lung biopsy (OLB). The authors feel that OLB does give a confidence to the treating physician to begin with a specific therapy in the form of steroids. But, as a matter of fact, at most health care delivery centres in the country, facilities for OLB are not available. Hence, the specific therapy should be instituted presumptively following an overall suggestion of disease based upon the clinical, physiological (chiefly comprising the pulmonary function test or PFT) and the radiological criteria, so that progression of disease could be arrested at an early stage.