Thrombi in left atrium can be detected with cardiac MRI

Kitkungvan et al report in the J Am CollCardiovascular Imaging that left atrial (LA) and left atrial appendage (LAA) thrombi can be detected with cardiac MRI (CMR) – without the need of a trans-esophageal echocardiogram (TEE) – before pulmonary vein isolation (PVI) is performed.

They studied 261 patients with congestive heart failure, hypertension, diabetes mellitus, stroke/transient ischemic attack, vascular disease, with CMR and TEE for evaluation of pulmonary venous anatomy before PVI. LA and LAA thrombi were evaluated by using CMR as follows: 1) cine-CMR; 2) contrast-enhanced magnetic resonance angiography; and 3) equilibrium phase delayed enhancement (DE) CMR with a long inversion time (TI) of 600 ms (long TI DE-CMR).

CMR and TEE were performed within 1.3 ± 2.3 days. LA/LAA thrombi were discovered in 9 patients (3.5%) by using TEE. Among the CMR techniques performed, long TI DE-CMR had the highest diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.2%), followed by contrast-enhanced magnetic resonance angiography accuracy (94.3%); sensitivity (66.7%); and specificity (95.2%) and cine-CMR accuracy (91.6%); sensitivity (66.7%); and specificity (92.5%).

The authors concluded that patients who were candidates for pulmonary vein isolation surgery, cardiac MRI with long inversion time delayed enhancement independently picked up LA and LAA clots in the same 3.5% of patients as did gold-standard TEE, thus CMR could be the single diagnostic study for assessment of pulmonary venous anatomy as well as presence of atrial thrombi thus reducing the number of pre-operative tests before PVI.

Liquid biopsy shows promise

The study by Sacher et al published in JAMA Oncology reported on “a blood test” that detects EGFR and KRAS mutations with rapid plasma genotyping of cell free DNA.

The objective of their study was to prospectively validate plasma droplet digital PCR (ddPCR) for the rapid detection of common epidermal growth factor receptor (EGFR) and KRAS mutations, as well as the EGFR T790M acquired resistance mutation.

Patients with advanced non-squamous non–small-cell lung cancer (NSCLC) who either had a new diagnosis and were planning period for initial therapy or had developed acquired resistance to an EGFR kinase inhibitor and were planned for rebiopsy underwent initial blood sampling and immediate plasma ddPCR for EGFR exon 19 del, L858R, T790M, and/or KRAS G12X between July 3, 2014, and June 30, 2015, at a National Cancer Institute–designated comprehensive cancer center. All patients underwent biopsy for tissue genotyping, which was used as the reference standard for comparison; rebiopsy was required for patients with acquired resistance to EGFR kinase inhibitors. Test turnaround time (TAT) was measured in business days from blood sampling until test reporting.

Of 180 patients with advanced NSCLC (62% female; median [range] age, 62 [37-93] years), 120 cases were newly diagnosed; 60 had acquired resistance. Tumor genotype included 80 EGFR exon 19/L858R mutants, 35 EGFR T790M, and 25 KRAS G12X mutants. Median (range) TAT for plasma ddPCR was 3 (1-7) days. Tissue genotyping median (range) TAT was 12 (1-54) days for patients with newly diagnosed NSCLC and 27 (1-146) days for patients with acquired resistance. Plasma ddPCR exhibited a positive predictive value of 100% for EGFR 19 del, 100% for L858R, and 100% for KRAS, but lower for T790M at 79%.  The sensitivity of plasma ddPCR was 82 for EGFR 19 del, 74% for L858R, and 77% for T790M, but lower for KRAS at 64%. Sensitivity for EGFR or KRAS was higher in patients with multiple metastatic sites and those with hepatic or bone metastases, specifically.

In conclusion, plasma ddPCR detected EGFR and KRAS mutations rapidly with the high specificity needed to select therapy and avoid unnecessary biopsies. The test accurately provided the information whether a patient with NSCLC lung cancer had a mutation that makes the disease treatable. It could also tell if less-fortunate patients had a different mutation, saving them weeks or months of treatment that would ultimately failed.  Finally, the noninvasive genotyping provides physicians with all the information they need thus the inherent risks of tissue genotyping due to repeated biopsies are avoided.

Breast MRI more accurate than mammography in diagnosing invasive cancer in high-risk women

A study by Sung et al published in Radiology found that breast MRI screening is more likely to detect invasive cancers than mammography in women at higher risk. 

The study was a retrospective review of 7,519 high-risk women due to family or personal history of breast cancer, high risk lesion, BRCA mutation status or radiation to the chest, who underwent MRI screening and mammography.

A total of 18 064 screening MR imaging examinations and 26 866 screening mammographic examinations were performed. Two hundred twenty-two cancers were diagnosed in 219 women, 167 (75%) at MR imaging, 43 (19%) at mammography, and 12 (5%) interval cancers. Median age at diagnosis was 52 years.  Cancers found at screening MR imaging were more likely to be invasive cancer 118 of 167 or 71%. Of the 43 cancers found at screening mammography, 38 (88%) manifested as calcifications and 28 (65%) were ductal carcinoma in situ. Interval cancers were associated with nodal involvement were of the triple-negative subtype.

In conclusion MRI of the breast was better than mammography in detecting invasive breast cancer in women at high risk for breast cancer.  Mammography had an advantage for the detection of calcifications and thus for ductal carcinoma in situ.

Stent Retriever Therapy of Benefit to Stroke Patients

A multicenter trial the results of which were published in Radiology by Goyal et al indicated that if a patient with acute ischemic stroke is treated within two and half hours of ictus, 91% recover with little or no disability.  However after five and a half hours, favorable outcome goes down to 41%.

Data from 196 patients enrolled in the SWIFT PRIME trial, a global, multicenter, prospective study in which outcomes of patients treated with intravenous tissue plasminogen activator tPA alone or in combination with a thrombectomy device (Solitaire by Covidien, Irvine, CA) were analyzed.

In the stent retriever arm of the study, symptom onset to reperfusion time of 150 minutes or less led to 91% estimated probability of functional independence, which decreased by 10% over the next hour and by 20% with every subsequent hour of delay. Time from arrival at the emergency department to arterial access was 90 minutes (interquartile range, 69–120 minutes), and time to reperfusion was 129 minutes (interquartile range, 108–169 minutes). Patients who initially arrived at a referring facility had longer symptom onset to groin puncture times compared with patients who presented directly to an endovascular-capable center (275 versus 179.5 minutes, P < .001).

The findings of the trial strongly suggest that fast reperfusion leads to improved functional outcome among patients with acute stroke treated with stent retrievers and tPA.

In Pursuit of Slaves

Captain John Gabriel Stedman (1744-1797) was a professional soldier who fought to suppress an 18th-century slave rebellion in Suriname and subsequently published the March Through a Swamp in Pursuit of Slaves. Although slavery was not abolished in Suriname until 1873, the publication of Stedman’s narrative in 1790 helped to erode public support for the slave trade in Europe and its colonies. The book was translated into several languages and published in more than 25 editions. Stedman’s descriptions of the brutality of plantation life debunked the myth that slavery was a benign, civilizing influence. By his own admission, Stedman was a mercenary, who also told the truth, and his narrative endures as a case study of violence and human rights abuses. To counter the argument that slaves were better off on New World plantations than living under comparatively primitive conditions in their native lands, Stedman storied that in the Maroon rebellion the slaves preferred to endure hardships and fight in order to escape get their freedom.

JAMA. 2015;314(5):434-435