舊金山——在美國心臟病學(xué)會(huì)(ACC)主辦的經(jīng)導(dǎo)管心血管治療(TCT)年會(huì)上公布的一項(xiàng)涉及254例患者和484處病變的研究顯示，與CT血管造影或侵入性冠狀動(dòng)脈造影的解剖評(píng)估相比，一種根據(jù)冠狀動(dòng)脈CT造影圖像計(jì)算血流儲(chǔ)備分?jǐn)?shù)的非侵入性檢查(FFRCT)在檢測(cè)缺血方面具有高度準(zhǔn)確性。

    該研究在丹麥奧爾胡斯大學(xué)和3個(gè)大洲的10個(gè)中心進(jìn)行，入選進(jìn)行CT和侵入性冠狀動(dòng)脈血管造影(檢查之間間隔不超過60天)的患者。主要終點(diǎn)是根據(jù)該新型FFRCT檢查的受試者工作特征曲線下面積(AUC)評(píng)估的其在診斷缺血方面的按患者診斷性能(與冠狀動(dòng)脈CT造影相比)。結(jié)果顯示，F(xiàn)FRCT的AUC為0.82，顯著優(yōu)于冠狀動(dòng)脈CT造影的0.63。與冠狀動(dòng)脈CT造影評(píng)估相比，F(xiàn)FRCT使特異性增加了近1倍。并且FFRCT正確將68%的CT血管造影假陽性病例重新歸類為真陰性。

    在254例患者中，F(xiàn)FRCT的準(zhǔn)確性為81%，而侵入性冠狀動(dòng)脈造影和CT血管造影解剖評(píng)估的準(zhǔn)確性分別為64%和53%。FFRCT的特異性為79%，而侵入性血管造影為51%，CT血管造影為34%。FFRCT的陽性預(yù)測(cè)值為65%，而侵入性血管造影為46%，CT血管造影為40%。在所有這些類別中，F(xiàn)FRCT的性能均顯著優(yōu)于CT血管造影。FFRCT按患者診斷的敏感性為86%，侵入性血管造影為91%，CT血管造影為94%。FFRCT的陰性預(yù)測(cè)值為92%，侵入性血管造影為93%，CT血管造影為92%。敏感性和陰性預(yù)測(cè)值的組間差異不顯著。

    484處病變的結(jié)果也表現(xiàn)出相似趨勢(shì)。FFRCT的準(zhǔn)確性為86%，侵入性血管造影為71%，CT血管造影為65%。三者的按血管特異性分別為86%、66%和60%，F(xiàn)FRCT的陽性預(yù)測(cè)值為61%，侵入性血管造影為40%，CT血管造影為33%。敏感性(分別為84%、84%和83%)和陰性預(yù)測(cè)值(95%、94%和92%)無顯著丟失。主要研究者Bjarne L. N?rgaard醫(yī)生表示，F(xiàn)FRCT和FFR侵入性評(píng)估的準(zhǔn)確性優(yōu)于其他檢查，包括負(fù)荷回聲、冠狀動(dòng)脈CT血管造影(cCTA)、使用腔內(nèi)衰減梯度的cCTA、單光子發(fā)射CT和血管內(nèi)超聲。

    評(píng)論專家指出，這種檢查將被整合入臨床實(shí)踐中。尚需進(jìn)形成本分析。預(yù)計(jì)未來2~3年，缺血的非侵入性評(píng)估將取得顯著進(jìn)展。該研究由FFRCT檢查的經(jīng)銷商HeartFlow資助。N?rgaard醫(yī)生聲明無其他經(jīng)濟(jì)利益沖突。評(píng)論專家聲明與多家藥企存在利益關(guān)系，但與HeartFlow無利益關(guān)系。

By: SHERRY BOSCHERT, Cardiology News Digital Network

SAN FRANCISCO – A noninvasive test that computes fractional flow reserve from coronary CT angiography images was highly accurate in detecting ischemia, compared with anatomic interpretation from CT angiography or invasive coronary angiography, in a study of 254 patients and 484 vessels.

The primary endpoint was per-patient diagnostic performance as assessed by the area under the receiver operating characteristic curve (AUC) of the test, compared with coronary CT angiography, for the diagnosis of ischemia. The AUC for the new test was 0.82, significantly better than 0.63 for coronary CT angiography, Dr. Bjarne L. N?rgaard reported at the Transcatheter Cardiovascular Therapeutics annual meeting.

The specificity nearly doubled when the HeartFlow test was used to compute fractional flow reserve from coronary CT angiography images (FFRCT), compared with coronary CT angiography assessment. FFRCT correctly reclassified 68% of false positives from CT angiography to true negatives, said Dr. N?rgaard of Aarhus (Denmark) University.

Invasive assessment of FFR is considered the gold standard for diagnosis of lesion-specific functional ischemic disease, but it carries more risk than a noninvasive test. Coronary CT angiography detects anatomic stenosis but is not good at determining the physiologic significance of lesions, he said.

The FFRCT technology builds a quantitative model using data from conventional coronary CT images, and develops a physiological model using left ventricular and coronary anatomy and established form-function principles, Dr. N?rgaard said. A fluid model calculates flow and pressure under simulated hyperemic conditions.

In the 254 patients, FFRCT had an accuracy of 81%, compared with 64% for anatomic assessment using invasive coronary angiography and 53% with CT angiography. The specificity was 79% with FFRCT, 51% with invasive angiography, and 34% with CT angiography. Positive predictive values were 65% with FFRCT, 46% with invasive angiography, and 40% with CT angiography. In each of these categories, FFRCT performed significantly better than CT angiography.
 
The sensitivity in per-patient diagnosis was 86% with FFRCT, 91% with invasive angiography, and 94% with CT angiography. The negative predictive values were 92% with FFRCT, 93% with invasive angiography, and 92% with CT angiography. Differences between groups were not significant for sensitivity and negative predictive values.

Similar trends were seen in results for the 484 vessels in the study. FFRCT had an accuracy of 86%, compared with 71% for invasive angiography and 65% for CT angiography. The per-vessel specificities were 86%, 66%, and 60%, respectively, and the positive predictive value was 61% with FFRCT, 40% with invasive angiography, and 33% with CT angiography. Again, there was no significant loss in sensitivity (84%, 84%, and 83%, respectively) or in negative predictive value (95%, 94%, and 92%).

The accuracy of FFRCT and invasive assessments of FFR compares favorably with the accuracy of other tests, Dr. N?rgaard said, including stress echo, coronary CT angiography (cCTA), cCTA with transluminal attenuation gradient, single-photon emission CT, and intravenous ultrasound.

"The diagnostic performance of other tests is not impressive," he added. "I think the FFR is a major breakthrough."

The study enrolled patients at 10 centers on three continents who underwent CT and invasive coronary angiography with no more than 60 days between tests.

"I think this will be incorporated into practice," Dr. James B. Hermiller Jr. commented in a panel discussion of the study during a press briefing. A cost **ysis is needed, added Dr. Hermiller of St. Vincent Heart Center of Indiana, Indianapolis.

Dr. Philippe Généreux, of H?pital du Sacré-Coeur de Montréal, called the trial "a brilliant study" and "a breath of fresh air" in the area of noninvasive testing.

Dr. Bernard J. Gersh of the Mayo Clinic, Rochester, Minn., said, "This is a really important trial." He predicted that over the next 2-3 years, great strides will be made in noninvasive assessments of ischemia. "Stay tuned. A number of other methods for evaluating FFR" are being studied, he noted.

The meeting was cosponsored by the American College of Cardiology.

HeartFlow, which markets the FFRCT test, funded the study. Dr. N?rgaard reported having no other financial disclosures. Dr. Hermiller, Dr. Généreux, and Dr. Gersh reported financial associations with multiple companies, but not with HeartFlow.