Cardiac MRI viability study and its role in revascularization- Excerpts from a tertiary care cardiac centre

Funding Acknowledgements

Type of funding sources: None.

Background

Assessment of cardiac viability based revascularization has not convincingly demonstrated, to improve patient outcomes statistically even by large trials like STITCH and PPAR-2 using SPECT and PET analysis. Here we used cardiac viability by cardiac MRI to guide us for revascularization and also found out problems arising in the statistical analysis for the same

Methods

It is a retrospective observational longitudinal follow up study whereby patients who had ischemic cardiomyopathy (confirmed with coronary angiogram) and who were admitted with features of heart failure or with acute coronary syndrome and who subsequently underwent cardiac MRI viability testing during the period from 1/02/2017 to 31/01/2020 were included. Patients were excluded who had non ischemic cardiomyopathy. Using cardiac MRI- LVEF, RVEF, Wall motion severity Index and Total viability percentage were additionally computed and analyzed. Patients were deemed having viable myocardium on ≤50% LGE in cardiac MRI and final treatment of CABG, PCI or only medical management was analyzed for the Primary end points of CV mortality, non-fatal CVA and non-fatal AMI 

Results

Based on the criteria total of 94 patients were selected for the study, 53 patients kept on only medical management, 19 patients underwent PCI and 22 patients had CABG. The baseline characteristics of the study population were an average age of 60years, male (76%) with Diabetes Mellitus(69%) and Hypertension (41.5%) in them. Coronary Angiogram showed that 10.6% patients had LM involvement, 92% had LAD disease, 72% patients had LCX lesion and 74% had RCA disease. While average Echo LVEF was 35.82%, Cardiac MRI based mean LVEF was 30.78%. It was found that patients who were kept only on medical management had higher Wall motion Severity Index (2.05) over patients who  were treated with PCI (1.94) or CABG (1.80) (p = 0.006). Also it was found that the Total viability percentage was less in patients kept only on medical management (74%) vs patients who were treated with PCI (78%) or CABG (77.8%)(p = 0.08) .It was found by cardiac MRI that patients with significant LAD lesions with viable LAD territory, those who underwent CABG or PCI based therapy had lesser mortality(7.69%,10%) over patients kept only on medical management (23%) (p = 0.407). Among patients with significant LAD lesions with non-viable LAD territory, those who underwent CABG or only medical management had lesser mortality (11.5%) than patients who underwent PCI (50%) (p = 0.137).

Conclusion(s)

Cardiac MRI based viability testing may guide the physician for optimal treatment but it does not reach statistical significance. The reasons maybe different arterial segments having different viability and anatomical hazards acting as cofounding factors. Viability being a continuum process does not follow a strict cut off of 50% LGE and 100% acute occluded vessel may not allow LGE.

Germline BRCA1 mutation and survival analysis in familial breast cancer patients in Kerala; South India

Mutations in breast cancer susceptibility gene BRCA1 have been identified in breast or breast/ovarian cancer families from different ethnic background. We analyzed a total of 79 samples for BRCA1 mutation, using Conformation Sensitive Gel Electrophoresis (CSGE) followed by sequencing. The overall survival of BRCA1 mutation carriers was also investigated. BRCA1 mutation was detected in 11 out of the 29 (38%) patients. Four different alterations were detected of three which were novel. A missense mutation in exon 7, 465G>A was detected in 1 patient (9%). Another missense mutation 932 G>A was observed in three patients (27.3%) and a truncation mutation 1027delA, was observed in one patient (9%). The fourth type of mutation (185delAG) which also results in protein truncation was observed in 6 different patients (54.5%). Kaplan-Meier survival analysis revealed a median overall survival of 34 months for BRCA1 mutation positive breast cancer patients and 71 months for BRCA1 negative breast cancer patients. The median overall survival of BRCA1 truncation mutation carriers was 26 months. Our data showed high prevalence of BRCA1 gene mutation among breast or breast/ovarian cancer families in South India and breast cancer patients having BRCA1 mutations were associated with poor prognosis.

Novel germline mutations in BRCA2 gene among 96 hereditary breast and breast-ovarian cancer families from Kerala, South India

PURPOSE

Aim of the present study was to identify the genetic heterogeneity, prevalence and frequency of germline mutations of BRCA2 gene in Hereditary Breast/Ovarian cancer patients from Kerala, South India.

METHODS

We analyzed 102 Breast/Ovarian cancer patients from 96 breast and/ovarian cancer families for BRCA2 gene mutations using Conformation-Sensitive Gel Electrophoresis (CSGE) followed by sequencing.

RESULTS

Sequence variations in BRCA2 gene were detected in 27 (26.4%) patients. Sixteen distinct sequence variants were detected of which 11 were (69%) in exon 11. We have identified two novel disease-causing frameshift mutations (c.4642delAA and c.4926insGACC) in two unrelated patients. Apart from this, fourteen distinct sequence variants were detected in 25 breast/ovarian cancer patients of which 8 (57%) were also novel. These include nine missense mutations, one silent mutation, one-nonsense mutation and three intronic variants.

CONCLUSIONS

The results of this study suggest that germline mutations of BRCA2 gene account for rather small proportion of Hereditary Breast/Ovarian cancer in Kerala, South India.

The cytogenetic identification of high risk members in colorectal cancer families

Family history of colorectal cancer is recognized as a risk factor for the disease and the development of colorectal cancer represents a suitable model for illustrating multistep tumor development. Bleomycin induced chromosome sensitivity studies were done in 7 colorectal cancer families consisting of 12 colorectal cancer patients and their 34 first degree relatives and 12 sporadic colorectal patients for comparison and identification of high risk family members with genetic instability. All patients and 4 unaffected relatives showed increased bleomycin sensitivity, which might be due to defective DNA repair system. These four relatives may be classified as high risk (without cancer at present) individuals. The study is being continued in more number of familial colorectal cancer patients and their relatives to arrive at definite conclusions.

DNA repair proficiency: a potential marker for identification of high risk members in breast cancer families

Breast cancer is the single largest cancer and causes the high rate of cancer mortality among women. A positive family history of breast cancer is recognized as one of the major risk factors for this disease. The present study evaluates bleomycin (BLM)-induced chromosome sensitivity analysis in breast cancer families which provides indirectly a measure of the DNA repair defect of each person. BLM sensitivity assay on cultured lymphocytes of 36 familial breast cancer patients, their 85 first or second degree female relatives, 36 sporadic breast cancer patients and 40 age- and sex-matched controls (without any family history of cancer) were carried out to measure interindividual variation in their DNA repair capacity through mutagen-induced chromosome sensitivity analysis. Fifty percent of familial breast cancer patients and seven unaffected relatives showed hypersensitivity. Compared to hyposensitive relatives these seven subjects may be considered as high risk individuals.