*Kenichi Tsujita, MD, PhD Seigo Sugiyama, MD, PhD Hideki Shimomura, MD, PhD Kenshi Yamanaga, MD Koichi Kaikita, MD, PhD Seiji Hokimoto, MD, PhD Hisao Ogawa, MD, PhD for the PRECISE-IVUS Investigators *Department of Cardiovascular Medicine Graduate School of Medical Sciences Kumamoto University Honjo, Chuo-ku, Kumamoto 860-8556 Japan E-mail: tsujita@kumamoto-u.ac.jp http://dx.doi.org/10.1016/j.jacc.2015.10.041 Please note: This work was supported in part by a Grant-in-Aid for Young Scientists B (22790713, 24790769) and a Grant-in-Aid for Scientific Research C (26461075) from the Ministry of Education, Science, and Culture, Japan (to Dr. Tsujita). Dr. Ogawa has received remuneration for lectures from Bayer, Boehringer Ingelheim, Daiichi-Sankyo, MSD, Pfizer, and Takeda; has received trust research/joint research funds from Bayer, Daiichi-Sankyo, and Novartis; and has received scholarship funds from AstraZeneca, Astellas, Bristol-Myers Squibb, Chugai, Daiichi-Sankyo, Dainippon Sumitomo Pharma, Kowa, MSD, Otsuka, Pfizer, Sanofi, Shionogi, and Takeda. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. REFERENCES 1. Tsujita K, Sugiyama S, Sumida H, et al. Impact of dual lipid-lowering strategy with ezetimibe and atorvastatin on coronary plaque regression in patients with percutaneous coronary intervention: the multicenter randomized controlled PRECISE-IVUS trial. J Am Coll Cardiol 2015;66: 495–507. 2. Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014;63: 2889–934. 3. Boekholdt SM, Hovingh GK, Mora S, et al. Very low levels of atherogenic lipoproteins and the risk for cardiovascular events: a meta-analysis of statin trials. J Am Coll Cardiol 2014;64:485–94. 4. Cannon CP, Blazing MA, Giugliano RP, et al. Ezetimibe added to statin therapy after acute coronary syndromes. N Engl J Med 2015;372: 2387–97. 5. Group HTC, Landray MJ, Haynes R, et al. Effects of extended-release niacin with laropiprant in high-risk patients. N Engl J Med 2014;371:203–12. Reconsidering the Impact of Pre-Operative Malperfusion on Acute Type A Dissection The Modified Penn Classification We read with great interest the recent article re- ported by Czerny et al. (1) who performed an analysis of a large database to address an important issue showing that malperfusion remained a severe clinical condition with strong potential for adverse outcomes in patients of acute type A aortic dissection (ATAAD) undergoing surgery while the impact differed substantially in accordance with the number and the type of organ malperfusion involved. Therefore, they proposed a classification system of “complicated” and “uncomplicated” ATAAD to help predict risk of outcomes. We want to congratulate the investigators for shedding light on the important issue of the impact of malperfu- sion on operative mortality risk for patients with ATAAD. The investigators provided valuable scien- tific evidences which confirmed and extended the viewpoint of ischemic consequences of organ mal- perfusion and end-organ dysfunction that compro- mised survival (2,3), although some investigators still argued that generalized ischemia in ATAAD predicted early surgical outcomes only (4). The issue of generalized ischemia caused by circulatory collapse, distinct from localized organ ischemia, is a very well taken point to be emphasized as the most important predictor of outcome after surgical repair of ATAAD and associated with the highest in- hospital mortality regardless of treatment strategy (3–5). In 2009, Augoustides et al. (2) reported an observational study of mortality risk stratification by ischemic presentation in patients with ATAAD, so-called Penn classification, which has been vali- dated by subsequent investigators (see references 1 and 5 in Chien et al. [5]) and has shown merit to be a useful risk assessment system in predicting ATAAD-related in-hospital mortality (4,5). Never- theless, Penn classification might still underesti- mate the surgical risk of ATAAD in the setting with critical organ-specific ischemia (including mesen- teric ischemia, sustained major cerebral ischemia, and coronary malperfusion). From this point of view, we have proposed to modify the original Penn classification and suggested to divide the Penn class Ab into subclasses Ab-1 and Ab-2 (Table 1) (5). Based on this consideration, we studied the relationship of ischemic presentations to 30-day mortality after surgical repair in 179 pa- tients from 1997 to 2014 (mean age, 59  12 years; 124 men; classes Aa [n ¼ 60], Ab-1 [n ¼ 44], Ab-2 [n ¼ 27], Ac [n ¼ 10], and Abc [n ¼ 38]). It was found that subclass Ab-2 had much higher mortality rate than that of subclass Ab-1 (22.2% vs. 2.3%), however, without statistical significance (p ¼ 0.175). One possible explanation is the small number of our patients suffered from localized malperfusion (Ab-1 or Ab-2). Nevertheless, we do think that subclass Ab-2 remains a surgical challenge and is JACC VOL. 67, NO. 1, 2016 Letters JANUARY 5/12, 2016:116 – 25 121