Abstract Background: Coronary artery disease (CAD) is a leading cause of worldwide mortality, and percutaneous coronary intervention (PCI) has long been used to alleviate its symptoms. However, patient anxiety has been noted to exacerbate the negative symptoms of CAD, as well as reduce the effectiveness of PCI. Numerous techniques have been developed for alleviating patient stress, such as mindfulness and breathing exercises, though their efficacy with respect to improving PCI outcomes has still not been fully defined. In this study, we aimed to shed light by examining whether CAD patients who underwent such exercises demonstrated lowered anxiety and improved functional outcomes post-PCI compared to CAD patients who did not undergo these procedures. Methods: One hundred and sixty CAD patients were enrolled and randomly divided into two 80-member groups, one of which (intervention) was prescribed meditation therapies, in the form of 6-min mindfulness videos, breathing therapies carried out 12 times per cycle, for 3 times/day, as well as targeted psychological counseling. The other 80-patient group served as the untreated control (Con). Anxiety was monitored during that time period using the Zung’s Self-rating Anxiety Scale (SAS), while sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI); furthermore, various cardiac functioning parameters, such as heart rate, were measured. In addition, the occurrence of serious adverse events (SAEs) was monitored during the 3-month follow-up period post-PCI. Results: No significant differences were present between the intervention and Con groups for baseline patient characteristics, except for body mass index. However, the intervention group had lower stress levels, in the form of lower SAS, compared to baseline, while the opposite was true for the untreated Con group. Lower SAS also corresponded to lower PSQI pre-PCI in intervention, indicating that this group had improved sleep quality, while PSQI remained unchanged from baseline to PCI in Con. Along with lower stress levels, intervention had lower blood pressures, heart rate, and SAEs, compared to Con, both pre-PCI and during the 3-month follow-up period, illustrating that meditation and respiratory therapies are able to reduce stress pre-PCI, in turn improving PCI outcomes and reducing complications postprocedure. Conclusion: Meditation and respiratory therapies are able to effectively alleviate anxiety and improve sleep quality pre-PCI, in turn improving cardiac functional parameters and facilitating smooth PCI procedures. All of these improvements resulted in increased PCI success rates, lowered hospitalization time, and reduced postsurgical complications in the form of SAEs, enabling these strategies to be of great clinical utility for better preparing CAD patients for the procedure. Public Registration: ClinicalTrials.gov identifier is NCT05320848.