CT-Guided Lipid-Lowering Therapy Leading to Functional Resolution of Ischemia

Abstract

Background

Aggressive lipid-lowering therapy may lead to regression of atherosclerosis; there are scarce data supporting such an approach for improving coronary physiological indexes. Serum low-density lipoprotein cholesterol is the primary target for lipid-lowering therapy. Computed tomography (CT)–derived assessments of plaque composition and coronary physiology are promising targets for individualized lipid-lowering strategies.

Case Summary

A 62-year-old woman presented with intermittent angina on moderate exertion. Coronary CT angiography revealed a significant focal stenosis in the left circumflex artery (fractional flow reserve based on CT [FFR_CT]: 0.74, pressure pullback gradient: 0.75) and non–flow-limiting diffuse disease in the left anterior descending artery (FFR_CT: 0.83, pressure pullback gradient: 0.59). CT-guided intensive lipid-lowering therapy was initiated. Follow-up showed a reduction in total plaque volume (−97 mm³ [Δ19%]), improvement in FFR_CT in the left circumflex artery (0.93) and left anterior descending artery (0.88), and resolution of symptoms.

Discussion

This case demonstrates that CT-guided lipid-lowering therapy can reverse plaque burden and ischemia in a patient with a flow-limiting epicardial lesion. The therapeutic targets proposed here, addressing both morphological plaque characteristics and coronary physiology parameters, go beyond the traditional goal of lowering low-density lipoprotein cholesterol levels. Pharmacological strategy guided by precise plaque imaging and functional assessment requires confirmation in larger clinical studies.

Take-Home Message

CT-guided pharmacotherapy aimed at improving both plaque composition and epicardial coronary flow parameters may represent an alternative to uniform treatment strategies based on cholesterol levels.

Visual Summary

Visual Summary.

CT-Guided Lipid-Lowering Therapy Leading to Functional Resolution of Ischemia

ASA = acetylsalicylic acid (aspirin); CCS = Canadian Cardiovascular Society; CT = computed tomography; DASH = Dietary Approaches to Stop Hypertension; FFR_CT = CT-derived fractional flow reserve; HTN = hypertension; LAD = left anterior descending artery; LCx = left circumflex artery; LDL = low-density lipoprotein; PPG-CT = CT-derived pressure pullback gradient; RCA = right coronary artery; TPV = total plaque volume.

Coronary artery disease (CAD) is the leading cause of death in the United States and Europe. Managing symptomatic CAD involves confirming the significance of epicardial coronary stenosis, followed by percutaneous coronary intervention or coronary artery bypass grafting when appropriate. While aggressive lipid-lowering therapy may lead to the regression of atherosclerosis, there is no agreement that such an approach can achieve the same physiological results as invasive revascularization. Serum low-density lipoprotein cholesterol (LDL-C) is the main target for lipid-lowering therapies. CT-derived quantitative assessments of coronary plaque composition and epicardial vessel physiology (eg, CT-derived fractional flow reserve [FFR_CT]) have emerged as promising candidates for measuring the effect of lipid-lowering therapy.¹ However, whether these measures can become new therapeutic targets for lipid-lowering therapy remains debatable. This case report demonstrates a practical application of CT-guided medical therapy in clinical practice.

Take-Home Message

• •CT-guided pharmacotherapy aimed at improving both plaque composition and epicardial coronary flow parameters may represent an alternative to uniform treatment strategies based on cholesterol levels.

Case Presentation

A 62-year-old woman with a history of hypertension and 20 years of smoking presented with intermittent angina on moderate exertion (Canadian Cardiovascular Society grade 2), which progressively worsened over several months. On admission, her blood pressure was 142/83 mm Hg, LDL-C was 98 mg/dL (2.53 mmol/L), and C-reactive protein was <6 mg/L (0.052 mmol/L). Electrocardiogram showed a nomogram with sinus rhythm, narrow QRS complexes, and no ischemic ST-T wave abnormalities. According to the European Society of Cardiology risk factor–weighted clinical likelihood model, the patient's probability of obstructive CAD was low (14%).

Guideline-directed medical therapy was initiated, including perindopril and bisoprolol for symptom control, along with rosuvastatin 10 mg for lipid management. The patient was advised to follow a Mediterranean-style diet and increase her amount of physical activity. A coronary computed tomography angiography (CCTA; Revolution EVO, GE Healthcare) was ordered, which was performed with 80 mL of contrast (Omnipaque 350) and 0.8 mg of sublingual nitroglycerin. It revealed a calcium score of 85, moderate diffuse stenosis in the left anterior descending artery (LAD), and moderate focal stenosis in the left circumflex artery (LCx) with evidence of positive remodeling. A functional assessment using FFR_CT (HeartFlow Inc) confirmed significant ischemia in the LCx (FFR_CT: 0.74), and borderline value in the LAD (FFR_CT: 0.83). A CT-derived pressure pullback gradient (PPG_CT) confirmed a diffuse lesion pattern in LAD (PPG_CT: 0.40) and a focal lesion in the LCx (PPG_CT: 0.75).² The length of functional disease, defined as a drop of FFR_CT >0.015 per millimeter, was 39.4 mm in the LAD and 21.2 mm in the LCx. The overall classification was CAD-RADS (Coronary Artery Disease Reporting and Data System) 3/F, indicating moderate CAD with functionally significant ischemia in the LCx with positive vascular remodeling.

At this point, invasive coronary angiography was offered to the patient but was not accepted. Based on CCTA findings and clinical judgment, her cardiovascular risk was reclassified to very high, and an LDL-C goal of <40 mg/dL was set. To achieve this, lipid-lowering therapy was escalated to rosuvastatin 40 mg combined with ezetimibe 10 mg. Aspirin 75 mg daily was introduced. A lipid panel confirmed an excellent therapeutic response to modified lifestyle and high-intensity lipid-lowering therapy, with LDL-C reduction to 34 mg/dL (0.88 mmol/L).

At the 8-month follow-up, the patient's angina resolved, and her blood pressure was reduced to 123/75 mm Hg. Repeat CCTA (Revolution Apex, GE Healthcare) was performed with 60 mL of contrast agent (Omnipaque 350) and 0.8 mg sublingual nitroglycerin. It demonstrated an overall CAD-RADS classification of 1, improved FFR_CT of 0.88 in the LAD and 0.93 in the LCx (Figure 1), and a diffused lesion pattern (PPG_CT: 0.47 in the LAD and 0.35 in the LCx). The length of functional disease decreased to 33.7 mm (−5.7 mm) in the LAD and to 16.8 mm (−4.4 mm) in the LCx. A quantitative plaque analysis (Medis Suite Angio CT, Medis Medical Imaging Systems BV) of baseline and follow-up CCTA images was conducted. Baseline total plaque volume (TPV) was 525 mm³, consisting of 486 mm³ of noncalcified plaque, including 39 mm³ of necrotic core and 39 mm³ of calcified plaque. At follow-up, TPV decreased by 19% (99 mm³), with reductions mainly across lipidic plaque by 97% (143 mm³). The necrotic core was practically eliminated, decreasing by 97% to 1 mm³. The calcified plaque volume increased by 103% to 81 mm³ (Figures 2 and 3). The observed reduction in TPV was reassessed and confirmed by an independent core laboratory (HeartFlow Inc). Plaque baseline total vessel volume was 1940 mm³. At follow-up, the vessel volume increased to 2,213 mm³, driven by improved vessel dilatation, as evidenced by an increase in lumen volume from 1,412 to 1783 mm³. The reduction in plaque burden correlated inversely with enhancements in vessel physiology, as shown in Table 1. Given the substantial improvements in plaque volume, lipid profile, functional lesion severity, and clinical symptoms, the patient no longer met the criteria for invasive coronary angiography.

Figure 1.

Physiological Assessment of Coronary Arteries at Baseline and After 8 Months of Intensive Lipid-Lowering Therapy

FFR_CT = CT-derived fractional flow reserve; LAD = left anterior descending artery; LCx = left circumflex artery; LDL = low-density lipoprotein; RCA = right coronary artery.

Figure 2.

Quantitative Coronary Plaque Analysis by Plaque Type at Baseline and After 8 Months of Intensive Lipid-Lowering Therapy

LDL = low-density lipoprotein.

Figure 3.

Quantitative Coronary Plaque Analysis in the LAD, LCx, and RCA at Baseline and After 8 Months of Intensive Lipid-Lowering Therapy

TPV = total plaque volume; other abbreviations as in Figure 1.

Table 1.

Quantitative Coronary Plaque Analysis and Physiological Assessment at Baseline and After 8 Months of Intensive Lipid-Lowering Therapy

	Baseline						8-Month Follow-Up						Change
	Vessel Volume, mm3	Lumen Volume, mm3	Plaque Volume (Fibrous/Fibrous Fatty/NC/Calcium), mm3	PAV	Lipidic Volume (Fibrous Fatty/NC), mm3	FFRCT	Vessel Volume, mm3	Lumen Volume, mm3	Plaque Volume (Fibrous/Fibrous Fatty/NC/Calcium), mm3	PAV	Lipidic Volume (Fibrous Fatty/NC), mm3	FFRCT	TPV, mm3	PAV	Lipidic Volume, mm3	ΔFFRCT
Total	1940	1,412	526 (339/108/39/40)	32%	147 (108/39)	n/a	2,213	1783	428 (342/3/1/81)	19%	4 (3/1)	n/a	−98 (–19%)	−8%	−143 (–97%)	n/a
LAD	972	658	312 (200/55/25/32)	25%	80 (55/25)	0.83	990	778	210 (156/2/0/52)	21%	2 (2/0)	0.88	−101 (−33%)	−11%	−78 (–98%)	+0.05
LCx	341	256	85 (54/17/6/7)	21%	23 (17/6)	0.74	395	335	59 (42/0/0/17)	15%	0 (0/0)	0.93	−26 (−31%)	−10%	−23 (–100%)	+0.19
RCA	627	498	129 (85/36/8/0)	27%	44 (36/8)	0.92	828	670	158 (143/2/1/12)	19%	3 (2/1)	0.94	+29 (+22%)	−1%	−42 (–95%)	+0.02

FFR_CT = CT-derived fractional flow reserve; LAD = left anterior descending artery; LCx = left circumflex artery; n/a = not applicable; NC = necrotic core; PAV = percentage atheroma volume; RCA = right coronary artery; TPV = total plaque volume.

Discussion

We present a clinical case demonstrating plaque regression in a symptomatic patient with obstructive CAD, confirmed through serial CCTA, FFR_CT, quantitative plaque analysis, and clinical assessment. The baseline CCTA findings indicated an elevated plaque risk attributed to the focal pattern of CAD, positive vascular remodeling, and a high plaque burden characterized by low-attenuation components.

This case illustrates a favorable response to early and intensive pharmacotherapy in managing significant coronary lesions. It underscores the potential of CT-guided, aggressive lipid-lowering therapy, achieving LDL-C targets typically reserved for patients with recurrent ischemic events, to reduce plaque burden and alleviate myocardial ischemia. The observed subsequent increase in coronary flow may potentially reduce the need for invasive interventions.

Regression of coronary atherosclerosis has been well documented in prior studies. The ASTEROID trial found that high-intensity statin therapy with rosuvastatin 40 mg daily achieved a mean LDL-C of 60.8 mg/dL, resulting in a 6.8% reduction in TPV as measured by intravascular ultrasound over 24 months.³ The EVAPORATE trial showed that adding icosapent ethyl to statin therapy led to a 17% reduction in low-attenuation plaque volume on CCTA compared with placebo over 18 months.⁴ Similarly, studies including a subanalysis of PACMAN-AMI (alirocumab on top of statin) and the DISCO trial (strict dietary modification) demonstrated regression of noncalcified plaque on CCTA.^5,6 A large meta-analysis confirmed that the degree of atheroma volume reduction is directly proportional to the achieved LDL-C level at follow-up.⁷ A subgroup analysis of patients with optimally modified LDL-C showed an increase in FFR.⁸ There have been 2 case reports showing improvement in perfusion imaging and FFR_CT in patients on medical therapy.^9,10

In the present case, an LDL-C level of 34 mg/dL was achieved and sustained for 6 months. We observed an improvement in FFR_CT of +0.19, accompanied by a 26 mm³ (−31%) reduction in lesion-specific plaque volume. However, the optimal intensity and duration of LDL-C lowering required to induce meaningful plaque regression remain uncertain. Similarly, the precise threshold of plaque volume reduction necessary to translate into clinically significant improvements in coronary physiology is yet to be clearly established.

Several favorable factors in this case may have contributed to the observed outcome. First, the patient's relatively low baseline LDL-C of 98 mg/dL allowed for the achievement of a markedly low follow-up LDL-C of 34 mg/dL using widely available oral lipid-lowering agents—rosuvastatin 40 mg and ezetimibe 10 mg. Second, the plaque morphology was predominantly noncalcified, consisting of fibrous fatty and necrotic core components, which are known to respond more favorably to pharmacologic intervention. Third, the lesion was focal and lipidic in nature; evidence from intravascular imaging studies suggests that focal lesions, often characterized by circumferential lipid-rich cores, are more amenable to regression with intensive lipid-lowering therapy. Finally, the absence of diabetes likely played a role, as multiple studies have shown that diabetes mellitus is associated with a diminished response to plaque regression therapies.

FFR_CT is currently used to identify coronary lesions that may benefit from revascularization and to assist in procedural planning, such as stent length selection. In the case presented, the observed correlation between plaque volume and functional lesion severity highlights the potential for FFR_CT to evolve beyond diagnostic use—serving as a tool to guide medical therapy. Specifically, it may help quantify the degree of plaque regression necessary to achieve a meaningful reduction in the physiological significance of coronary stenosis.

We should highlight that the results are notably more pronounced than those reported in large intravascular imaging trials. The magnitude and rapidity of change in the current case appear unusually favorable. The TPV reduction mainly resulted from a profound 97% decrease in lipid-rich plaque, with near-total resolution of the necrotic core. This finding may underlie the improvement in lesion-specific coronary flow dynamics.

We cannot exclude the possibility that our findings may to some degree reflect technical variability inherent to CTA-based plaque quantification. Although the plaque analysis was performed in a standardized fashion, the absence of follow-up invasive angiography limits anatomical validation. No inflammatory markers were collected, which limits our ability to assess this risk factor.

In conclusion, this case illustrates the potential of CT-guided intensive lipid-lowering therapy to reduce coronary ischemia, plaque burden, and clinical symptoms in obstructive CAD. The observed improvements in plaque composition and FFR_CT values demonstrate the use of noninvasive imaging for guiding and monitoring medical therapy. This case report represents a hypothesis-generating observation rather than evidence of a generalizable treatment paradigm. Therefore, caution should be used when extrapolating the findings beyond the individual case described. The question remains open whether CT-guided medical intervention for obstructive CAD instead of an invasive strategy provides clinical benefits in selected patients.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.