Outcomes of patients with high bleeding risks characteristics presenting with acute coronary syndrome undergoing percutaneous coronary intervention

Background

Patients with high bleeding risk characteristics (HBR) presenting with acute coronary syndrome (ACS) pose a clinical challenge to balance risk for recurrent ischemic events versus incurring bleeding with dual antiplatelet therapy.

Purpose

We seek to determine the incidence and predictors of short and long term ischemic and bleeding outcomes in patients with HBR factors presenting with ACS after percutaneous coronary intervention (PCI).

Method

Consecutive patients over a 1-year period, who underwent PCI for ACS were categorized as having HBR based on: age ≥75, anemia (hemoglobin<110g/L), thrombocytopenia (platelet<100x109/L), renal failure (eGFR<30umol/L) or concurrent use of oral anticoagulation. Primary outcome was major adverse cardiovascular event (MACE) defined as composite of cardiovascular death, myocardial infarction, and stroke at 1 year. Key secondary outcomes include significant bleeding defined as Bleeding Academic Research Consortium (BARC) type 3 or 5, and net adverse cardiovascular event (NACE), as a composite of MACE and significant bleeding.

Results

Of 1351 patients presented with ACS, 389 (28.8%) had at least one HBR criteria. At 1 year, patients with HBR, compared to those without, had increased MACE (11.1% vs 4.2%, p<0.001) and cardiovascular death (5.7% vs 1.7%, p<0.001). Patients with HBR had increased significant bleeding (3.6% vs 2.3%, p=0.011) and NACE (14.4% vs 5.4%, p<0.001). Multivariate analysis showed the presence of HBR and prior history of myocardial infarction were predictors for 1-year MACE (OR 2.67, CI [1.62–4.42], p<0.001 and OR 2.18, CI [1.29–3.70], p=0.004, respectively), whereas the use of second-generation antiplatelet agent was not. Increased MACE and NACE were observed in HBR patients beyond 1 month of DAPT.

Conclusion

Among patients with ACS undergoing PCI, those with HBR had higher risk for both ischemic and bleeding complications. Novel strategies need to be considered for this high-risk group. Current guidelines, recommending 1 year of DAPT for patients with ACS, should be re-evaluated among patients with HBR.

Funding Acknowledgement

Type of funding sources: None. Kaplan-Meier curve for 1 year MACEKaplan-Meier curve for 1 year death

Comparing clinical outcomes following 1 year of dual antiplatelet therapy in patients risk stratified by the PRECISE-DAPT and DAPT scores

Background

Dual antiplatelet therapy (DAPT) is the standard of care following PCI. DAPT reduces ischemic events but increases bleeding risk. Duration of DAPT following PCI remains controversial. Current guidelines recommend duration be individualized based on risk of ischemia and bleeding. Although multiple strategies exist to risk stratify patients, including application of the PRECISE-DAPT and DAPT scores, there is currently no standardized risk assessment protocol.

Purpose

To determine if the PRECISE-DAPT and DAPT scores can identify patients at increased risk of ischemia or bleeding in a cohort prescribed 12 months of DAPT following PCI.

Methods

We calculated the PRECISE-DAPT and DAPT scores for 469 consecutive patients at baseline after PCI. Patients were grouped based on score treatment recommendation; PRECISE-DAPT prolonged or shortened (PRECISE DAPT <25 vs. ≥25) and DAPT prolonged or shortened (DAPT ≥2 vs <2). End points included 1-year rates of major adverse cardiovascular events (MACE) and TIMI major or minor bleeding.

Results

Among 469 patients, mean age was 64.4 (SD 12.2); 102 (21.7%) were women. Index presentation consisted of a STEMI in 207 (44.1%), NSTEMI in 99 (21.1%), and UA in 60 (12.8%). At presentation, 174 (37.1%) were current smokers, 115 (24.5%) had a prior MI, 118 (25.2%) had diabetes, 249 (53.1%) had dyslipidemia and 281 (60.0%) were previously diagnosed as hypertensive. Overall, there was an increase in bleeding and no difference in MACE for patients with a PRECISE-DAPT score ≥25 (13.3% vs. 4.1% P<0.001). No difference in bleeding or MACE was present in patients stratified by the DAPT score.

Conclusion

A PRECISE-DAPT score ≥25 was associated with an increased rate of bleeding and no difference in MACE in patients prescribed 12 months of DAPT. This supports the use of the PRECISE-DAPT as a prospective tool in clinical practice.

Funding Acknowledgement

Type of funding source: None

P1933Comparing treatment recommendations for the DAPT and PRECISE-DAPT scores after percutaneous coronary intervention

Background

Dual antiplatelet therapy (DAPT), with aspirin and a P2Y12 inhibitor, is the standard therapy for patients following PCI. Duration of treatment with DAPT has been controversial despite large studies. Current guidelines recommend treatment duration be individualized based on risk of ischemia and bleeding. To facilitate treatment decisions, risk assessment tools, including the DAPT and PRECISE-DAPT scores, have been developed.

Purpose

As components of these scores differ, the variability of recommendation remains unknown. We set to evaluate inter-tool concordance in treatment recommendation in a cohort of patients after PCI.

Methods

Using data from our local PCI registry, we calculated the PRECISE-DAPT at baseline following PCI and the DAPT after 1 year of treatment for 311 consecutive patients with complete data for both scores to be calculated. Based on their DAPT and PRECISE-DAPT scores, patients were grouped into concordant for long-term treatment (DAPT ≥2 and PRECISE-DAPT <25) or concordant for shortened treatment (DAPT <2 and PRECISE- DAPT ≥25). All other patients were considered discordant. We then performed a concordance analysis using Cohen's kappa to measure degree of agreement.

Results

Among the 311 patients, mean age was 63.4 (SD 11.6); 245 (79%) were men, 93 (29.9%) had history of a prior MI, 130 (41.8%) were current smokers, 32 (10.3%) had a history of CHF or LVEF <30%, 82 (26.3%) had diabetes and 196 (63.0%) were previously diagnosed with hypertension. Index event consisted of a STEMI in 101 (32.4%), NSTEMI in 93 (29.9%), unstable angina in 27 (8.7%), stable angina in 67 (21.5%) and the remaining 23 (7.4%) had other indications for PCI. Mean DAPT score was 1.52 (SD 1.37). Mean PRECISE-DAPT was 17.65 (SD 12.73). The DAPT recommended long-term treatment for 162 (52.1%) and shortened treatment for 149 (47.9%). The PRECISE-DAPT recommended long-term treatment for 245 (78.9%) and shortened treatment for 66 (21.2%). The overall proportion of agreement between the two risk scores was 56.6% with a Cohen's kappa index of 0.110 (95% CI, 0.017 to 0.204). See Table.

Concordance Analysis PRECISE-DAPT Score Recommendation Long Term (N=245) Shortened (N=66) DAPT Score Recommendation Long Term (N=162) 136 (43.7%) 26 (8.4%) Concordant for Long Term Treatment Shortened (N=149) 109 (35%) 40 (12.8%) Concordant for Shortened Treatment

Conclusion

Comparison of the DAPT score and the PRECISE-DAPT score showed concordance in treatment recommendation in only 56.6% of patients. Given the poor agreement between these tools, prospective concurrent evaluations and correlation to outcomes will be required in future studies.

Older patients' preferences and views related to non-face-to-face diabetes chronic care management: a qualitative study from southeast Louisiana

Background: Management of diabetes may be uniquely challenging for older individuals with multiple chronic conditions. Health systems and policymakers have attempted to reduce barriers to chronic care management (CCM) through incentives to provide non-face-to-face care. This qualitative study aimed to investigate and present views on non-face-to-face care management held by elderly patients with diabetes and other chronic conditions in order to contribute to improved programming for this population. Materials and methods: Semi-structured interviews were conducted with patients over the age of 64 who have been diagnosed with diabetes and at least one other chronic health condition. Interview recordings were transcribed and analyzed by experienced researchers using a thematic analytic approach, and an illustrative case study was developed. Results: Thirty individuals participated in this study. Participants were drawn from three health systems in south Louisiana, an area with high rates of morbidity and mortality related to chronic diseases. We identified themes related to lived experiences with diabetes and other medical conditions, perception of personal health status, perceived value of non-face-to-face programs, and support needs for future programming. Additionally, we present one case study describing in detail an individual patient's experience with non-face-to-face CCM. Conclusion: Health systems should consider intentionally recruiting participants who would benefit most from non-face-to-face care, including higher-need, less self-sufficient patients with resource constraints, while continuing to offer in-person services. Future research should examine whether tailoring non-face-to-face programming and support to address unique barriers can further enhance diabetes care at the population level.

Parasitized Natural Killer cells do not facilitate the spread of Toxoplasma gondii to the brain

Toxoplasma gondii is a protozoan parasite capable of invading immune cells and co‐opting their migratory pathways to disseminate through the host. Natural Killer (NK) cells can be directly invaded by the parasite and this invasion alters NK cell migration, producing a hypermotile phenotype. However, the consequences of this hypermotile phenotype for the dissemination of T. gondii to the brain remain unknown. To address this, C57BL6/J mice were infected with freshly egressed tachyzoites (type IIPrugniaud strain) or with parasitized NK cells. Under both conditions, parasite loads in the brain were comparable, indicating that parasitized NK cells were not able to facilitate spread of T. gondii to the brain. Consistent with this, we found no evidence for the recruitment of endogenous NK cells to the brain at early time points post‐infection, nor any changes in the expression of α4β1 integrin, involved in recruitment of NK cells to the brain. We therefore found no evidence for a role for hypermotile NK cells in delivery of parasites to the brain during acute infection with T. gondii.

A prospective randomized evaluation of a pharmacogenomic approach to antiplatelet therapy among patients with ST-elevation myocardial infarction: the RAPID STEMI study

Treatment of carriers of the CYP2C19*2 allele and ABCB1 TT genotype with clopidogrel is associated with increased ischemic complications after percutaneous coronary intervention (PCI). We sought to evaluate a pharmacogenomic strategy among patients undergoing PCI for ST-elevation myocardial infarction (STEMI), by performing a randomized trial, enrolling 102 patients. Point-of-care genetic testing for CYP2C19*2, ABCB1 TT and CYP2C19*17 was performed with carriers of either the CYP2C19*2 allele or ABCB1 TT genotype randomly assigned to a strategy of prasugrel 10 mg daily or an augmented dosing strategy of clopidogrel (150 mg daily for 6 days then 75 mg daily). The primary end point was the proportion of at-risk carriers exhibiting high on-treatment platelet reactivity (HPR), a marker associated with increased adverse cardiovascular events, after 1 month. Fifty-nine subjects (57.8%) were identified as carriers of at least one at-risk variant. Treatment with prasugrel significantly reduced HPR compared with clopidogrel by P2Y12 reaction unit (PRU) thresholds of >234 (0 vs 24.1%, P=0.0046) and PRU>208 (3.3 vs 34.5%, P=0.0025). The sensitivity of point-of-care testing was 100% (95% CI 88.0-100), 100% (86.3-100) and 96.9% (82.0-99.8) and specificity was 97.0% (88.5-99.5), 97.1% (89.0-99.5) and 98.5% (90.9-99.9) for identifying CYP2C19*2, ABCB1 TT and CYP2C19*17, respectively. Logistic regression confirmed carriers as a strong predictor of HPR (OR=6.58, 95% CI 1.24-34.92; P=0.03). We confirmed that concurrent identification of three separate genetic variants in patients with STEMI receiving PCI is feasible at the bedside. Among carriers of at-risk genotypes, treatment with prasugrel was superior to an augmented dosing strategy of clopidogrel in reducing HPR.

Abstract 4653: Role of serum HE4 in studying ovarian cancer progression and response to therapy with ARCHITECT HE4 assay

Human epididymis protein 4 (HE4) is a whey acidic four-disulfide core protein. Serum HE4 has been shown to be a promising biomarker for epithelial ovarian cancer (EOC) with manual HE4 EIA assays. The ARCHITECT system is one of the major automated formats for cancer immunodiagnostics. This abstract describes the clinical performance of an investigational ARCHITECT HE4 assay in the measurement of serum HE4 from longitudinal samples of subjects with EOC and single-point samples from healthy subjects, and subjects with malignancy, benign diseases, EOC or other malignant diseases.

PROCEDURES: The ARCHITECT HE4 Assay is a paramagnetic microparticle chemiluminescent assay adopting the sensitive CHEMIFLEX® technology. Single-point and longitudinal serum samples were tested with an investigational ARCHITECT HE4 Assay reagent lot on the ARCHITECT i2000SR. Single-point sera were collected from healthy subjects (N = 400), subjects with pregnancy (N = 50) and benign disease (N = 612), and subjects which were diagnosed with EOC (N = 314) and other cancers (N = 250) including endometrial, breast, gastrointestinal, lung, and bladder cancer. Longitudinal sera (N = 506), including initial time point and follow-up visits (average = 5.7 per subject), were collected from subjects (N = 76) which were diagnosed with EOC. All of the single-point and longitudinal samples were handled in accordance with IRB-approved and GCP-compliant protocols.

RESULTS: Using an ARCHITECT HE4 cut-off value of &gt;140 pmol/L, the percent distributions of ARCHITECT HE4 by cohort are: 3% of healthy subjects, 0% with pregnancy, 7.2% of subjects with benign diseases, 53.5% with EOC and 28.4% with other cancers. Using the upper 95% point of the distribution of the HE4 ratio at 14% to categorize the successive HE4 readings into those that were and were not significantly elevated for the longitudinal samples, the sensitivity, specificity and positive predictive value of HE4 elevation versus disease progression were 53.4% (95% CI: 44.1%-62.5%), 78.8% (95% CI: 74.7% - 82.4%) and 43.2% (95% CI: 32.9% - 54.1%) respectively. The total concordance between HE4 elevation and disease progression was 73%. Receiver Operator Characteristic analysis showed an area under the curve of 0.685 (SE = 0.033) for the diagnosis of progression from the ratio of successive HE4 readings. When comparing the change of the HE4 ratio with the diagnostic response to therapy, a decrease in HE4 reflected response to therapy with a sensitivity of 82% and a specificity of 53%.

CONCLUSIONS: The study with single-point samples has shown the utility of ARCHITECT HE4 values as a serum biomarker for EOC. The longitudinal increase of ARCHITECT HE4 values in sera seemed to be effective in recognizing the progression of EOC. The longitudinal decrease of ARCHITECT HE4 values in sera seemed to correlate with the response of EOC subjects to therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4653.

Role of circulating tumour cells in predicting recurrence after excision of primary colorectal carcinoma

BACKGROUND

This study assessed the potential for reverse transcriptase-polymerase chain reaction (RT-PCR)-based circulating tumour cell identification to predict colorectal cancer recurrence.

METHODS

mRNA for carcinoembryonic antigen and cytokeratin 20 was identified by RT-PCR in blood from patients with colorectal cancer, before and after primary tumour resection. Cancer recurrence was assessed at follow-up, and the accuracy of RT-PCR and primary tumour lymph node positivity in predicting recurrence was estimated.

RESULTS

One hundred and ninety-six patients with colorectal cancer were studied over a median follow-up of 1393 days from surgery. Regression analysis selected 24-h post-resection RT-PCR positivity (hazard ratio for a positive test in predicting recurrence 8.66 (95 per cent confidence interval (c.i.) 3.08 to 24.33)) before lymph node involvement (hazard ratio 7.92 (95 per cent c.i. 3.26 to 19.20)). When 24-h post-resection RT-PCR was combined with lymph node positivity, the hazard ratio increased to 18.54 (95 per cent c.i. 4.01 to 85.11), attributing a 3 per cent recurrence risk to 52 per cent, and a 50 per cent recurrence risk to 48 per cent, of patients with colorectal cancer resected with curative intent.

CONCLUSION

RT-PCR positivity within 24 h of primary colorectal cancer resection is a strong predictor of colorectal cancer recurrence, and may be useful clinically.

Predicting the clinical outcome of tetanus: the tetanus severity score

OBJECTIVES

To create a new tetanus score and compare it with the Phillips and Dakar scores.

METHODS

We used prospectively acquired data from consecutive patients admitted to the Hospital for Tropical Diseases, Ho Chi Minh City, to create the Tetanus Severity Score (TSS) with multivariate logistic regression. We compared the new score with Phillips and Dakar scores by means of resubstituted and prospective data, assessing performance in terms of sensitivity, specificity and area under receiver operator characteristic curves.

RESULTS

Resubstitution testing yielded a sensitivity of 77% (298/385) and a specificity of 82% (1,183/1,437) for the TSS; 89% (342/385) and 20% (281/1,437) for the Phillips score; and 13% (49/385) and 98% (1,415/1,437) for the Dakar score. The TSS showed greatest discrimination with 0.89 area under the receiver operator characteristic curve (95% CI 0.88-0.90); this was 0.74 for the Dakar score and (95% CI 0.71-0.77) and 0.66 for the Phillips score (95% CI 0.63-0.70; P values <0.001). Prospective testing showed 65% (13/20) sensitivity and 91% (210/230) specificity for the TSS; 80% (16/20) and 51% (118/230) for the Phillips score; and 25% (5/20) and 96% (221/230) for the Dakar score. The TSS achieved the greatest area under TSS of 0.89 (95% CI 0.82-0.96), significantly greater than the Phillips score [0.74 (0.6-0.88), P = 0.049] but not the Dakar score [0.80, (0.71-0.90), P = 0.090].

CONCLUSIONS

The TSS is the first prospectively developed classification scheme for tetanus and should be adopted to aid clinical triage and management and as a basis for clinical research.

Derivation of a toxicity-based model to predict how water chemistry influences silver toxicity to invertebrates

The effect of altering water chemistry on acute silver toxicity to three invertebrate species, two Daphnids, Daphnia magna and Daphnia pulex, as well as an amphipod Gammarus pulex was assessed. In addition, the physiological basis of Ag(I) toxicity to G. pulex was examined. Daphnia magna and D. pulex were more sensitive than G. pulex and 48 h LC(50) values in synthetic ion poor water were 0.47, 0.65 and 2.1 microg Ag(I) l(-1), respectively. Increasing water [Cl(-)] reduced Ag(I) toxicity in all species, and increasing water [Ca(2+)] from 50 to 1,500 microM reduced Ag(I) toxicity in G. pulex. Whole body Na(+) content, but not K(+) or Ca(2+) was significantly reduced in G. pulex exposed to 6 microg Ag(I) l(-1) for 24 h, but there was no inhibition of whole body Na(+)/K(+)-ATPase activity. Both increasing water [Cl(-)] and [Ca(2+)] reduced this Ag(I)-induced Na(+) loss. For D. magna, the presence of 10 mg l(-1) humic acid or 0.5 microM 3-mercaptoproprionic acid (3-MPA) increased the 48 h LC(50) values by 5.9 and 58.5-fold, respectively, and for D. pulex the presence of 1 microM thiosulfate increased the 48 h LC(50) value by four-fold. The D. magna toxicity data generated from this study were used to derive a Daphnia biotic ligand model (BLM). Analysis of the measured LC(50) values vs. the predicted LC(50) values for toxicity data from the present and published results where water Cl(-), Ca(2+), Na(+) or humic acid were varied showed that 91% of the measured toxicity data fell within a factor of two of the predicted LC(50) values. However, the daphnid BLM could not accurately predict G. pulex toxicity. Additionally, the Daphnia BLM was under-protective in the presence of the organic thiols 3-MPA or thiosulphate and predicted an increase in the LC(50) value of 114- and 74-fold, respectively. The Daphnia toxicity based BLM derived from the present data set is successful in predicting Daphnia toxicity in laboratory data sets in the absence of sulfur containing compounds, but shows its limitations when applied to waters containing organic thiols or thiosulphate.

Serum tryptophan decrease correlates with immune activation and impaired quality of life in colorectal cancer

Cancer-related indoleamine (2,3)-dioxygenase up-regulation by interferon-gamma might influence quality of life by depleting serum tryptophan. We correlated serum tryptophan levels with immune activation and quality of life in patients with colorectal liver metastases. Venous blood was sampled from patients with primary colorectal cancer and from patients with metachronous colorectal liver metastases who completed quality of life and psychological questionnaires. Serum tryptophan, kynurenine, neopterin, interleukin 2 soluble receptor alpha (IL-2 sRalpha), soluble tumour necrosis factor receptor I (sTNF RI), interleukin 6, and C-reactive protein were measured. Liver metastasis volume was estimated by computerised tomography, and survival from blood sampling was noted. Sixty-six patients with colorectal cancer were studied (39 males; median age 66 years) of whom 25 had colorectal liver metastases only (17 males; median age 62 years; median liver metastasis volume 208 ml; median survival 234 days). Reduced serum tryptophan was significantly associated with Rotterdam Symptom Checklist physical symptom (r=-0.51, P=0.01) and Sickness Impact Profile (r=-0.42, P=0.04) scores, and correlated with increased serum neopterin (r=-0.36, P=0.003), IL-2 sRalpha (r=-0.51, P=0.01) and sTNF RI (r=-0.45, P=0.02) levels. Stepwise regression analyses suggested that serum tryptophan was an independent predictor of Rotterdam Symptom Checklist physical symptom (regression coefficient -20.78, P=0.01) and Sickness Impact Profile (regression coefficient -109.09, P=0.04) scores. The results supported a role for interferon-gamma-mediated serum tryptophan decrease in cancer-induced quality of life deterioration.

Accuracy of investigations for asymptomatic colorectal liver metastases

PURPOSE

The aim of this study was to prospectively assess the accuracy of the most promising imaging and tumor marker tests in liver metastasis diagnosis on follow-up of asymptomatic colorectal cancer patients during a median of 57 months after primary tumor resection.

METHODS

One hundred patients, who were considered free of liver metastases after primary colorectal cancer resection and conventional follow-up, were screened for liver metastases by computerized tomography, magnetic resonance and ultrasound scans, ultrasound Doppler and isotope assessment of changes in hepatic arterial and portal venous flow, and serum estimation of carcinoembryonic antigen. Patients were followed up during a median of 41 months to identify those who developed liver metastases.

RESULTS

The most sensitive technique was computerized tomography (sensitivity 0.67, specificity 0.91). Computerized tomography and magnetic resonance but not ultrasound were 100 percent accurate in differentiating liver metastases from other hepatic lesions. Techniques based on changes in hepatic arterial and portal venous flow had lower diagnostic accuracies (Doppler perfusion index, sensitivity 0.58, specificity 0.57; hepatic perfusion index, sensitivity 0.50, specificity 0.55), whereas ultrasound scanning identified only 43 percent (sensitivity 0.43, specificity 0.96) and serum carcinoembryonic antigen 33 percent (sensitivity 0.33, specificity 0.81) of patients with asymptomatic liver metastasis. Sensitivity could be improved by using tests in combination but this reduced specificity.

CONCLUSIONS

Computerized tomography was the most sensitive test for asymptomatic colorectal liver metastases, but only 67 percent of affected patients were identified.

Correlation between tumour blood flow and fluorouracil distribution in a hypovascular liver metastasis model

The poor response of colorectal liver metastases to fluorinated pyrimidine chemotherapy may be due to poor drug penetration into the tumour. Chemotherapy delivered by the blood to well perfused areas of tumour must reach less well perfused areas by diffusion. This study examined the relationship between intratumoural blood flow and drug uptake in a hypovascular liver metastasis animal model. We used a double isotope technique to examine the microdistribution of the blood flow tracer [125I]-iodoantipyrine (IAP) and fluorinated pyrimidine 5-[6-3H]-fluorouracil (5-FU) within intrahepatic, hypovascular HSN tumours. There was a significant fall (P < 10(-6)) in both IAP and 5-FU uptake between the liver/tumour edge and tumour centre which resulted in a significant covariation (P < 10(-5)) in tracer uptake with distance. The finding of a close covariation between blood flow and drug uptake in liver metastases suggested that 5-FU diffusion did not compensate for low 5-FU delivery in areas of poor tumour blood flow. The lower 5-FU levels in low compared with high areas of tumour blood flow could reduce the cytotoxic effect and increase the potential for development of drug resistance.

Continuous angiotensin II infusion increases tumour: normal blood flow ratio in colo-rectal liver metastases

Insufficient blood flow within colo-rectal hepatic metastases is a factor which may limit drug delivery to, and thus the response of, these tumours to regional chemotherapy. Loco-regional flow may be manipulated pharmacologically to enhance the tumour blood flow relative to that of the normal liver. However, as yet, only transient effects have been studied. Patients receiving regional chemotherapy for unresectable hepatic disease were given a 45 min regional infusion of the vasoconstrictor Angiotensin II. Intrahepatic blood flow distribution was assessed serially by Positron Emission Tomography (PET) imaging together with the trapping tracer copper(II) pyruvaldehyde bis(N-4-methylthiosemicarbazone) (Cu-PTSM) labelled using copper-62. Eleven lesions in nine patients were studied, with no adverse effects. Prior to Angiotensin II administration tumour blood flow was generally found to be greater than that of liver (10/11 lesions; 8/9 patients; median TNR 1.3, iqr 0.9-2.5). A significant increase in relative flow to tumour was seen in response to 10 min Angiotensin II infusion in most cases (7/11 lesions; 7/9 patients; median TNR 2.1, iqr 1.4-4.1; P = 0.008), which appeared to be sustained throughout the 45 min infusion period (median TNR 1.85, iqr 1.3-3.8; P = 0.03). These effects were accompanied by transient elevation of mean arterial pressure, but no change in pulse rate. These observations suggest that prolonged regional vasoconstrictor administration could prove useful in the management of unresectable colo-rectal hepatic metastases, and that further development of vascular manipulation to enhance tumour targeting and drug delivery is warranted.

Acute outcome with the flexicut directional coronary atherectomy catheter for the treatment of coronary in-stent restenosis

In-stent restenosis (ISR) is a growing problem that is without a practical, efficacious treatment strategy. The purpose of this study was to determine the acute outcome of 17 patients with coronary ISR who were treated with the new 8 French (Fr), guide-catheter compatible Flexicut directional atherectomy catheter (Guidant Corporation, Santa Clara, California). Failure to deliver the device occurred in 2/17 ISR lesions. The remaining 15 ISR lesions were successfully debulked (e.g., minimum lumen diameter pre-procedure: 0.30 +/- 0.16 mm; post-atherectomy plus adjuvant therapy: 2.16 +/- 0.57 mm). Of note, the reference vessel diameter was only 2.62 +/- 0.63 mm. In 11/15 tissue specimens, macroscopic or microscopic particles consistent with stent material were found. There was an absence of acute closure or elevations of creatinine phosphokinase levels. Apart from 1 patient who developed recurrent restenosis, all other patients demonstrated either clinical improvement or lack of restenosis during early clinical follow-up (mean, 5 months). We conclude that use of the Flexicut catheter provides satisfactory debulking and early clinical outcomes in patients with ISR. Long-term follow-up of these and additional patients will be helpful in determining the efficacy of the Flexicut atherectomy catheter for the treatment of ISR.

Focal arterial transgene expression after local gene delivery

BACKGROUND

Gene therapy for the treatment of vascular disease is limited by a low transfection efficiency and/or undesired biological responses.

OBJECTIVE

To determine the transfection efficiency of delivering a liposome/DNA complex into balloon-injured rabbit arteries systematically or using a local delivery catheter.

METHODS

The cationic liposomes N-[1-(2,3-dioleoyloxy) propyl]-N,N,N-trimethylammonium methyl-sulphate and dioleoyl-phosphatidylethanolamine were mixed 1:1 (wt/wt) and combined with the plasmid pCMV-AP containing the human placental alkaline phosphatase (AP) reporter gene. Before initiating the in vivo experiments, the optimal ratio of liposome to DNA complex and the persistence of transgene expression were determined in cultured vascular smooth muscle cells (SMC). In vivo, a Dispatch catheter was used for local delivery of the liposome/DNA complex into rabbit iliac arteries that had been balloon injured five days previously. The contralateral iliac or renal artery was also balloon injured, and liposomes with normal saline were delivered as a negative control. For the systemic delivery group, the liposome/DNA complex was delivered through an ear vein.

RESULTS

AP expression in transfected SMC persisted for 28 days in vitro, although the percentage of transfected cells declined with time (eg, at 24 h it was 27.3%+/-2.9%, at 28 days it was 0.4%+/-0.1%). SMC proliferation in vitro enhanced the transfection efficiency 12-fold. In vivo, local delivery resulted in low levels of transfection in arteries harvested one day postdelivery; however, six of seven arteries harvested three days postdelivery had multiple regions of focal transgene expression involving all three arterial layers. For the systemic delivery group, two of nine arteries expressed the transgene. No transgene expression was found in uninjured arteries in either the local or systemic delivery groups. However, with both local and systemic delivery, balloon-injured arteries that received liposomes and saline showed low levels of AP expression in either the neointima, media or adventitia, presumably due to systemic recirculation of the liposome/AP construct.

CONCLUSIONS

Liposome-mediated gene transfection can be successfully performed to all vessel layers in vivo by using a local delivery catheter, and may provide a therapeutic opportunity for modulating atherosclerosis and restenosis. Unwanted transfection at a distance may occur with catheter-based local delivery and requires further refinement.

Venesection needle coring increases positive results with RT-PCR for detection of circulating cells expressing CEA mRNA

We assessed whether circulating cell positivity using RT-PCR for carcinoembryonic antigen (CEA) cDNA was affected by venesection via a needle compared with a pre-aspirated venous cannula, and by increased PCR cycles. Systemic blood was sampled by needle and pre-aspirated cannula in 101 healthy individuals with no cancer history. After erythrocyte removal, samples were subjected to RT-PCR using specific primers for CEA, with 29 or 35 RT-PCR cycles. There was a significant difference between the number of subjects whose samples were negative when collected via needle venesection and positive when collected via pre-aspirated cannula, compared with positive by needle venesection and negative by pre-aspirated cannula for both 29 (P = 0.016) and 35 (P = 0.0111) RT-PCR cycles. Venesection technique (P = 0.01) and number of cycles (P = 0.003) were significant predictors of a positive result. Positive results in healthy subjects were reduced to less than 3% when an aspirated cannula was used for venesection and >29 PCR cycles were avoided.

Pathophysiological insights from studies of retrieved coronary atherectomy tissue

Coronary atherectomy offers the intuitive advantage of removing tissue mass in order to improve blood flow. A second major benefit of atherectomy is the opportunity to study lesion tissue and make pathophysiological insights. The value of the latter cannot be over emphasized, as current animal models for the study of atherosclerosis and restenosis are fraught with limitations. In this review, we outline some of the key descriptive findings that have emerged from the study of atherectomy specimens. Specifically, we will focus on the role of smooth muscle cell proliferation, thrombus organization and matrix formation in primary atherosclerotic lesions, as well as restenotic lesions after balloon angioplasty and stenting.