library_construction_protocol: AC and PA  artery tissue from patients undergoing  endarterectomy and was immediately collected from the operating room and transferred on ice for tissue dissociation. Samples were weighed, minced with surgical blades, then placed in conical tubes with pronase (5000U/ml) and collagenase II (0.1% solution). Tissue was then incubated at 37C for one hour with continuous gentle agitation. 30min into the incubation period, DNase I solution was added, and the entire solution remained incubated for an additional 30min. Pipetting mixture up and down every 10min helped break tissue apart. After one-hour incubation was complete, 10% FBS+Complete EC media (Cell Applications, Inc) was immediately added to dissociated tissue to quench enzymatic activity. The sample was then inverted a few times and then set down for 30sec, allowing all debris to settle at the bottom. The entire solution was carefully transferred, without settled debris, to another conical tube (use pipettor to transfer solution near debris pellet carefully, removing all solution but leaving pellet at bottom of tube). Sample was then centrifuged at 500g for 5min and supernatant discarded. Cell pellet was resuspended in 5mL 1X RBC lysis buffer and incubated at RT for 5min. 30mL 1X PBS was added to stop the reaction and the sample was then spun immediately at 500g for 5min at RT. The supernatant was discarded, and cell pellet resuspended in 10mL FACS buffer composed of: 1X PBS, 2.5mM EDTA, 25mM HEPES, 1% FBS (heat-inactivated), and 1% Pen-Strep. To wash excess reagents, the sample is centrifuged again at 500g for 5min, supernatant discarded, then cell pellet is again resuspended in 2mL FACS buffer. 2ul of 5mM DRAQ5 is added to each tube, and solution is pipetted up and down a few times. Next, solution is triturated with P1000 and entire sample sieved through 100uM cell strainer fitted onto 50mL conical tube. This step is repeated next through a 40uM cell strainer. The solution is placed on ice and immediately transported for FACS. Cells were sorted on a MoFLo Astrios EQ cell sorter (Beckman Coulter) with a 100 µm nozzle tip at a sheath pressure of 20 psi. Cells were distinguished from cellular debris by gating DRAQ5 positive events and doublets excluded using appropriate FSC and SSC gating. (Extended Data Fig. 1a-d). Cells isolated represented <1% of the total particles in the sample which was then transported for evaluation of viability and subsequent sequencing. Cells were then processed on the 10X Genomics Chromium single cell 3' v3 gene expression platform. Cells were counted and checked for viability using a Countess II Automated Cell Counter (Thermo Fisher). Sequencing libraries were prepared as recommended in the user manual with cell target numbers ranging between 6,000 – 22,000 cells per sample. Completed sequencing libraries were then sequenced on an Illumina NextSeq500 using 28 x 91 paired-end reads with 8 base i7 index reads to demultiplex different samples. Aggregating our 6 samples (3 patient-matched PA and AC samples) resulted in 51,981 cells, a sequencing depth of 15,549 reads/cell, 1,339 median genes/cell and 3,776 UMI/cell.